call GNUNET_SERVER_receive_done() also on internal error paths
[oweals/gnunet.git] / src / transport / gnunet-service-transport_neighbours.c
index f1095095a0afe446ba7e629d32ba52d9380aa5c9..17e30c0b790c087e1fa50710426f32b7d4b7175d 100644 (file)
@@ -1,6 +1,6 @@
 /*
      This file is part of GNUnet.
-     (C) 2010-2015 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
@@ -38,7 +38,6 @@
 #include "transport.h"
 
 
-
 /**
  * Size of the neighbour hash map.
  */
@@ -59,7 +58,7 @@
 /**
  * How long are we willing to wait for a response from ATS before timing out?
  */
-#define ATS_RESPONSE_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 5000)
+#define ATS_RESPONSE_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)
 
 /**
  * How long are we willing to wait for an ACK from the other peer before
  * usual SETUP_CONNECTION_TIMEOUT as we do not inform the
  * higher layers about the disconnect during this period.
  */
-#define FAST_RECONNECT_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 1)
-
-/**
- * How long are we willing to wait for a response from the blacklist
- * subsystem before timing out?
- */
-#define BLACKLIST_RESPONSE_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 500)
+#define FAST_RECONNECT_TIMEOUT GNUNET_TIME_UNIT_SECONDS
 
 /**
  * Interval to send utilization data
  */
-#define UTIL_TRANSMISSION_INTERVAL GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 1)
+#define UTIL_TRANSMISSION_INTERVAL GNUNET_TIME_UNIT_SECONDS
 
 /**
  * State describing which kind a reply this neighbour should send
@@ -373,7 +366,7 @@ struct NeighbourMapEntry
   /**
    * ATS address suggest handle
    */
-  struct GNUNET_ATS_SuggestHandle *suggest_handle;
+  struct GNUNET_ATS_ConnectivitySuggestHandle *suggest_handle;
 
   /**
    * Time where we should cut the connection (timeout) if we don't
@@ -382,11 +375,6 @@ struct NeighbourMapEntry
    */
   struct GNUNET_TIME_Absolute timeout;
 
-  /**
-   * Latest calculated latency value
-   */
-  struct GNUNET_TIME_Relative latency;
-
   /**
    * Tracker for inbound bandwidth.
    */
@@ -424,16 +412,6 @@ struct NeighbourMapEntry
    */
   enum GST_ACK_State ack_state;
 
-  /**
-   * Tracking utilization of outbound bandwidth
-   */
-  uint32_t util_payload_bytes_sent;
-
-  /**
-   * Tracking utilization of inbound bandwidth
-   */
-  uint32_t util_payload_bytes_recv;
-
   /**
    * Tracking utilization of outbound bandwidth
    */
@@ -520,16 +498,14 @@ static unsigned long long bytes_in_send_queue;
 /**
  * Task transmitting utilization data
  */
-static struct GNUNET_SCHEDULER_Task * util_transmission_tk;
-
-/**
- * FIXME
- */
-static struct GNUNET_CONTAINER_MultiPeerMap *registered_quota_notifications;
+static struct GNUNET_SCHEDULER_Task *util_transmission_tk;
 
 
 /**
- * FIXME
+ * Convert the given ACK state to a string.
+ *
+ * @param s state
+ * @return corresponding human-readable string
  */
 static char *
 print_ack_state (enum GST_ACK_State s)
@@ -633,7 +609,6 @@ neighbours_changed_notification (const struct GNUNET_PeerIdentity *peer,
 }
 
 
-
 /**
  * Lookup a neighbour entry in the neighbours hash map.
  *
@@ -678,7 +653,8 @@ send_outbound_quota (const struct GNUNET_PeerIdentity *target,
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Sending outbound quota of %u Bps for peer `%s' to all clients\n",
-              ntohl (quota.value__), GNUNET_i2s (target));
+              ntohl (quota.value__),
+              GNUNET_i2s (target));
   q_msg.header.size = htons (sizeof (struct QuotaSetMessage));
   q_msg.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SET_QUOTA);
   q_msg.quota = quota;
@@ -698,49 +674,34 @@ static void
 free_address (struct NeighbourAddress *na)
 {
   if (GNUNET_YES == na->ats_active)
-  {
     GST_validation_set_address_use (na->address,
                                     GNUNET_NO);
-    GST_ats_set_in_use (na->address,
-                        na->session,
-                        GNUNET_NO);
-  }
-
-  na->bandwidth_in = GNUNET_BANDWIDTH_value_init (0);
-  na->bandwidth_out = GNUNET_BANDWIDTH_value_init (0);
-  na->ats_active = GNUNET_NO;
-  na->keep_alive_nonce = 0;
   if (NULL != na->address)
   {
+    GST_ats_block_address (na->address,
+                           na->session);
     GNUNET_HELLO_address_free (na->address);
     na->address = NULL;
   }
+  na->bandwidth_in = GNUNET_BANDWIDTH_value_init (0);
+  na->bandwidth_out = GNUNET_BANDWIDTH_value_init (0);
+  na->ats_active = GNUNET_NO;
+  na->keep_alive_nonce = 0;
   na->session = NULL;
 }
 
 
 /**
- * Set net state for this neighbour and notify monitoring
+ * Master task run for every neighbour.  Performs all of the time-related
+ * activities (keep alive, send next message, disconnect if idle, finish
+ * clean up after disconnect).
  *
- * @param n the respective neighbour
- * @param s the new state
+ * @param cls the `struct NeighbourMapEntry` for which we are running
+ * @param tc scheduler context (unused)
  */
 static void
-set_state (struct NeighbourMapEntry *n,
-          enum GNUNET_TRANSPORT_PeerState s)
-{
-  n->state = s;
-  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-             "Neighbour `%s' changed state to %s\n",
-             GNUNET_i2s (&n->id),
-             GNUNET_TRANSPORT_ps2s(s));
-  neighbours_changed_notification (&n->id,
-                                   n->primary_address.address,
-                                   n->state,
-                                   n->timeout,
-                                   n->primary_address.bandwidth_in,
-                                   n->primary_address.bandwidth_out);
-}
+master_task (void *cls,
+            const struct GNUNET_SCHEDULER_TaskContext *tc);
 
 
 /**
@@ -755,7 +716,36 @@ set_state_and_timeout (struct NeighbourMapEntry *n,
                       enum GNUNET_TRANSPORT_PeerState s,
                       struct GNUNET_TIME_Absolute timeout)
 {
+  if (GNUNET_TRANSPORT_is_connected (s) &&
+      ! GNUNET_TRANSPORT_is_connected (n->state) )
+  {
+    neighbours_connect_notification (&n->id,
+                                     n->primary_address.bandwidth_in,
+                                     n->primary_address.bandwidth_out);
+    GNUNET_STATISTICS_set (GST_stats,
+                          gettext_noop ("# peers connected"),
+                          ++neighbours_connected,
+                          GNUNET_NO);
+  }
+  if (! GNUNET_TRANSPORT_is_connected (s) &&
+        GNUNET_TRANSPORT_is_connected (n->state) )
+  {
+    GNUNET_STATISTICS_set (GST_stats,
+                          gettext_noop ("# peers connected"),
+                          --neighbours_connected,
+                          GNUNET_NO);
+    neighbours_disconnect_notification (&n->id);
+  }
   n->state = s;
+  if ( (timeout.abs_value_us < n->timeout.abs_value_us) &&
+       (NULL != n->task ) )
+  {
+    /* new timeout is earlier, reschedule master task */
+    GNUNET_SCHEDULER_cancel (n->task);
+    n->task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining (timeout),
+                                            &master_task,
+                                            n);
+  }
   n->timeout = timeout;
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "Neighbour `%s' changed state to %s with timeout %s\n",
@@ -771,29 +761,6 @@ set_state_and_timeout (struct NeighbourMapEntry *n,
 }
 
 
-/**
- * Set new state timeout for this neighbour and notify monitoring
- *
- * @param n the respective neighbour
- * @param timeout the new timeout
- */
-static void
-set_timeout (struct NeighbourMapEntry *n,
-            struct GNUNET_TIME_Absolute timeout)
-{
-  n->timeout = timeout;
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Neighbour `%s' changed timeout %s\n",
-              GNUNET_i2s (&n->id),
-              GNUNET_STRINGS_absolute_time_to_string (timeout));
-  neighbours_changed_notification (&n->id,
-                                   n->primary_address.address,
-                                   n->state, n->timeout,
-                                   n->primary_address.bandwidth_in,
-                                   n->primary_address.bandwidth_out);
-}
-
-
 /**
  * Initialize the alternative address of a neighbour
  *
@@ -825,9 +792,15 @@ set_alternative_address (struct NeighbourMapEntry *n,
     n->alternative_address.bandwidth_out = bandwidth_out;
     return;
   }
-  free_address (&n->alternative_address);
+  if (NULL != n->alternative_address.address)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Replacing existing alternative address with another one\n");
+    free_address (&n->alternative_address);
+  }
   if (NULL == session)
-    session = papi->get_session (papi->cls, address);
+    session = papi->get_session (papi->cls,
+                                 address);
   if (NULL == session)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
@@ -840,7 +813,8 @@ set_alternative_address (struct NeighbourMapEntry *n,
                               GNUNET_NO);
     return;
   }
-  GST_ats_new_session (address, session);
+  GST_ats_new_session (address,
+                       session);
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
               "Neighbour `%s' configured alternative address %s\n",
               GNUNET_i2s (&n->id),
@@ -852,6 +826,9 @@ set_alternative_address (struct NeighbourMapEntry *n,
   n->alternative_address.session = session;
   n->alternative_address.ats_active = GNUNET_NO;
   n->alternative_address.keep_alive_nonce = 0;
+  GNUNET_assert (GNUNET_YES ==
+                 GST_ats_is_known (n->alternative_address.address,
+                                   n->alternative_address.session));
 }
 
 
@@ -865,76 +842,67 @@ set_alternative_address (struct NeighbourMapEntry *n,
  *        address must be setup)
  * @param bandwidth_in inbound quota to be used when connection is up
  * @param bandwidth_out outbound quota to be used when connection is up
- * @param is_active #GNUNET_YES to mark this as the active address with ATS
  */
 static void
 set_primary_address (struct NeighbourMapEntry *n,
                      const struct GNUNET_HELLO_Address *address,
                      struct Session *session,
                      struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
-                     struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out,
-                     int is_active)
+                     struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
 {
-  struct GNUNET_TRANSPORT_PluginFunctions *papi;
-
-  if (NULL == (papi = GST_plugins_find (address->transport_name)))
-  {
-    GNUNET_break (0);
-    return;
-  }
   if (session == n->primary_address.session)
   {
-    n->primary_address.bandwidth_in = bandwidth_in;
-    n->primary_address.bandwidth_out = bandwidth_out;
-    if (is_active != n->primary_address.ats_active)
+    GST_validation_set_address_use (n->primary_address.address,
+                                    GNUNET_YES);
+    if (n->primary_address.bandwidth_in.value__ != bandwidth_in.value__)
     {
-      n->primary_address.ats_active = is_active;
-      GST_ats_set_in_use (n->primary_address.address,
-                          n->primary_address.session,
-                          is_active);
-      GST_validation_set_address_use (n->primary_address.address,
-                                      is_active);
+      n->primary_address.bandwidth_in = bandwidth_in;
+      GST_neighbours_set_incoming_quota (&address->peer,
+                                         bandwidth_in);
     }
-    if (GNUNET_YES == is_active)
+    if (n->primary_address.bandwidth_out.value__ != bandwidth_out.value__)
     {
-      GST_neighbours_set_incoming_quota (&address->peer, bandwidth_in);
-      send_outbound_quota (&address->peer, bandwidth_out);
+      n->primary_address.bandwidth_out = bandwidth_out;
+      send_outbound_quota (&address->peer,
+                           bandwidth_out);
     }
     return;
   }
-  free_address (&n->primary_address);
-  if (NULL == session)
-    session = papi->get_session (papi->cls, address);
+  if ( (NULL != n->primary_address.address) &&
+       (0 == GNUNET_HELLO_address_cmp (address,
+                                       n->primary_address.address)) )
+  {
+    GNUNET_break (0);
+    return;
+  }
   if (NULL == session)
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-               "Failed to obtain new session for peer `%s' and  address '%s'\n",
-               GNUNET_i2s (&address->peer), GST_plugins_a2s (address));
-    GNUNET_STATISTICS_update (GST_stats,
-                              gettext_noop ("# session creation failed"),
-                              1,
-                              GNUNET_NO);
+    GNUNET_break (0);
+    GST_ats_block_address (address,
+                           session);
     return;
   }
-  GST_ats_new_session (address, session);
+  if (NULL != n->primary_address.address)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Replacing existing primary address with another one\n");
+    free_address (&n->primary_address);
+  }
   n->primary_address.address = GNUNET_HELLO_address_copy (address);
   n->primary_address.bandwidth_in = bandwidth_in;
   n->primary_address.bandwidth_out = bandwidth_out;
   n->primary_address.session = session;
-  n->primary_address.ats_active = is_active;
   n->primary_address.keep_alive_nonce = 0;
-  if (GNUNET_YES == is_active)
-  {
-    /* Telling ATS about new session */
-    GST_ats_set_in_use (n->primary_address.address,
-                        n->primary_address.session,
-                        GNUNET_YES);
-    GST_validation_set_address_use (n->primary_address.address,
-                                    GNUNET_YES);
-    GST_neighbours_set_incoming_quota (&address->peer, bandwidth_in);
-    send_outbound_quota (&address->peer, bandwidth_out);
-  }
-
+  GNUNET_assert (GNUNET_YES ==
+                 GST_ats_is_known (n->primary_address.address,
+                                   n->primary_address.session));
+  /* subsystems about address use */
+  GST_validation_set_address_use (n->primary_address.address,
+                                  GNUNET_YES);
+  GST_neighbours_set_incoming_quota (&address->peer,
+                                     bandwidth_in);
+  send_outbound_quota (&address->peer,
+                       bandwidth_out);
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
               "Neighbour `%s' switched to address `%s'\n",
               GNUNET_i2s (&n->id),
@@ -959,45 +927,29 @@ static void
 unset_primary_address (struct NeighbourMapEntry *n)
 {
   /* Notify monitoring about change */
+  if (NULL == n->primary_address.address)
+    return;
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Disabling primary address\n");
   neighbours_changed_notification (&n->id,
                                    n->primary_address.address,
                                    n->state,
                                    n->timeout,
                                    GNUNET_BANDWIDTH_value_init (0),
                                    GNUNET_BANDWIDTH_value_init (0));
-  /* Unset primary address */
   free_address (&n->primary_address);
 }
 
 
-/**
- * Clear the alternative address of a neighbour since this address is not
- * valid anymore
- *
- * @param n the neighbour
- */
-static void
-unset_alternative_address (struct NeighbourMapEntry *n)
-{
-  /* Unset primary address */
-  free_address (&n->alternative_address);
-}
-
-
 /**
  * Free a neighbour map entry.
  *
  * @param n entry to free
- * @param keep_sessions #GNUNET_NO to tell plugin to terminate sessions,
- *                      #GNUNET_YES to keep all sessions
  */
 static void
-free_neighbour (struct NeighbourMapEntry *n,
-                int keep_sessions)
+free_neighbour (struct NeighbourMapEntry *n)
 {
   struct MessageQueue *mq;
-  struct GNUNET_TRANSPORT_PluginFunctions *papi;
-  struct GNUNET_HELLO_Address *backup_primary;
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Freeing neighbour state of peer `%s'\n",
@@ -1007,44 +959,29 @@ free_neighbour (struct NeighbourMapEntry *n,
   /* fail messages currently in the queue */
   while (NULL != (mq = n->messages_head))
   {
-    GNUNET_CONTAINER_DLL_remove (n->messages_head, n->messages_tail, mq);
+    GNUNET_CONTAINER_DLL_remove (n->messages_head,
+                                 n->messages_tail,
+                                 mq);
     if (NULL != mq->cont)
-      mq->cont (mq->cont_cls, GNUNET_SYSERR, mq->message_buf_size, 0);
+      mq->cont (mq->cont_cls,
+                GNUNET_SYSERR,
+                mq->message_buf_size,
+                0);
     GNUNET_free (mq);
   }
-  /* It is too late to send other peer disconnect notifications, but at
-     least internally we need to get clean... */
-  if (GNUNET_YES == test_connected (n))
-  {
-    GNUNET_STATISTICS_set (GST_stats,
-                          gettext_noop ("# peers connected"),
-                          --neighbours_connected,
-                          GNUNET_NO);
-    neighbours_disconnect_notification (&n->id);
-  }
-
   /* Mark peer as disconnected */
-  set_state (n, GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED);
-
-  if (NULL != n->primary_address.address)
-    backup_primary = GNUNET_HELLO_address_copy (n->primary_address.address);
-  else
-    backup_primary = NULL;
-
+  set_state_and_timeout (n,
+                         GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED,
+                         GNUNET_TIME_UNIT_FOREVER_ABS);
   /* free addresses and mark as unused */
   unset_primary_address (n);
-  free_address (&n->alternative_address);
-
-  /* cut all transport-level connection for this peer */
-  // FIXME: might want to revisit this; maybe just
-  // shorten session timeout on plugin level?
-  if ((GNUNET_NO == keep_sessions) &&
-      (NULL != backup_primary) &&
-      (NULL != (papi = GST_plugins_find (backup_primary->transport_name))))
-    papi->disconnect_peer (papi->cls, &n->id);
-
-  if (NULL != backup_primary)
-    GNUNET_HELLO_address_free (backup_primary);
+
+  if (NULL != n->alternative_address.address)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Cleaning up alternative address\n");
+    free_address (&n->alternative_address);
+  }
   GNUNET_assert (GNUNET_YES ==
                  GNUNET_CONTAINER_multipeermap_remove (neighbours,
                                                        &n->id, n));
@@ -1052,7 +989,7 @@ free_neighbour (struct NeighbourMapEntry *n,
   /* Cancel address requests for this peer */
   if (NULL != n->suggest_handle)
   {
-    GNUNET_ATS_suggest_address_cancel (GST_ats, &n->id);
+    GNUNET_ATS_connectivity_suggest_cancel (n->suggest_handle);
     n->suggest_handle = NULL;
   }
 
@@ -1092,7 +1029,8 @@ free_neighbour (struct NeighbourMapEntry *n,
  */
 static struct GNUNET_TIME_Relative
 send_with_session (struct NeighbourMapEntry *n,
-                   const char *msgbuf, size_t msgbuf_size,
+                   const void *msgbuf,
+                   size_t msgbuf_size,
                    uint32_t priority,
                    struct GNUNET_TIME_Relative timeout,
                   unsigned int use_keepalive_timeout,
@@ -1102,18 +1040,24 @@ send_with_session (struct NeighbourMapEntry *n,
   struct GNUNET_TRANSPORT_PluginFunctions *papi;
   struct GNUNET_TIME_Relative result = GNUNET_TIME_UNIT_FOREVER_REL;
 
-  GNUNET_assert (n->primary_address.session != NULL);
+  GNUNET_assert (NULL != n->primary_address.session);
   if ( ((NULL == (papi = GST_plugins_find (n->primary_address.address->transport_name)) ||
         (-1 == papi->send (papi->cls,
                            n->primary_address.session,
-                           msgbuf, msgbuf_size,
+                           msgbuf,
+                            msgbuf_size,
                            priority,
                            (result = (GNUNET_NO == use_keepalive_timeout) ? timeout :
-                               GNUNET_TIME_relative_divide (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT,
-                                                            papi->query_keepalive_factor (papi->cls))),
-                           cont, cont_cls)))) &&
+                             GNUNET_TIME_relative_divide (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT,
+                                                          papi->query_keepalive_factor (papi->cls))),
+                           cont,
+                            cont_cls)))) &&
        (NULL != cont))
-    cont (cont_cls, &n->id, GNUNET_SYSERR, msgbuf_size, 0);
+    cont (cont_cls,
+          &n->id,
+          GNUNET_SYSERR,
+          msgbuf_size,
+          0);
   GST_neighbours_notify_data_sent (n->primary_address.address,
                                   n->primary_address.session,
                                   msgbuf_size);
@@ -1122,19 +1066,6 @@ send_with_session (struct NeighbourMapEntry *n,
 }
 
 
-/**
- * Master task run for every neighbour.  Performs all of the time-related
- * activities (keep alive, send next message, disconnect if idle, finish
- * clean up after disconnect).
- *
- * @param cls the `struct NeighbourMapEntry` for which we are running
- * @param tc scheduler context (unused)
- */
-static void
-master_task (void *cls,
-            const struct GNUNET_SCHEDULER_TaskContext *tc);
-
-
 /**
  * Function called when the 'DISCONNECT' message has been sent by the
  * plugin.  Frees the neighbour --- if the entry still exists.
@@ -1143,11 +1074,14 @@ master_task (void *cls,
  * @param target identity of the neighbour that was disconnected
  * @param result #GNUNET_OK if the disconnect got out successfully
  * @param payload bytes payload
- * @param physical bytes physical
+ * @param physical bytes on wire
  */
 static void
-send_disconnect_cont (void *cls, const struct GNUNET_PeerIdentity *target,
-                      int result, size_t payload, size_t physical)
+send_disconnect_cont (void *cls,
+                      const struct GNUNET_PeerIdentity *target,
+                      int result,
+                      size_t payload,
+                      size_t physical)
 {
   struct NeighbourMapEntry *n;
 
@@ -1193,12 +1127,17 @@ send_disconnect (struct NeighbourMapEntry *n)
                                          &disconnect_msg.purpose,
                                          &disconnect_msg.signature));
 
-  (void) send_with_session (n, (const char *) &disconnect_msg,
-      sizeof (disconnect_msg), UINT32_MAX, GNUNET_TIME_UNIT_FOREVER_REL,
-      GNUNET_NO, &send_disconnect_cont, NULL );
+  (void) send_with_session (n,
+                            &disconnect_msg,
+                            sizeof (disconnect_msg),
+                            UINT32_MAX,
+                            GNUNET_TIME_UNIT_FOREVER_REL,
+                            GNUNET_NO,
+                            &send_disconnect_cont,
+                            NULL);
   GNUNET_STATISTICS_update (GST_stats,
-                            gettext_noop
-                            ("# DISCONNECT messages sent"), 1,
+                            gettext_noop ("# DISCONNECT messages sent"),
+                            1,
                             GNUNET_NO);
 }
 
@@ -1222,20 +1161,24 @@ disconnect_neighbour (struct NeighbourMapEntry *n)
   case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
   case GNUNET_TRANSPORT_PS_INIT_ATS:
     /* other peer is completely unaware of us, no need to send DISCONNECT */
-    free_neighbour (n, GNUNET_NO);
+    free_neighbour (n);
     return;
   case GNUNET_TRANSPORT_PS_SYN_SENT:
     send_disconnect (n);
-    set_state (n, GNUNET_TRANSPORT_PS_DISCONNECT);
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_DISCONNECT,
+                           GNUNET_TIME_UNIT_FOREVER_ABS);
     break;
   case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
     /* we never ACK'ed the other peer's request, no need to send DISCONNECT */
-    free_neighbour (n, GNUNET_NO);
+    free_neighbour (n);
     return;
   case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
     /* we DID ACK the other peer's request, must send DISCONNECT */
     send_disconnect (n);
-    set_state (n, GNUNET_TRANSPORT_PS_DISCONNECT);
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_DISCONNECT,
+                           GNUNET_TIME_UNIT_FOREVER_ABS);
     break;
   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
   case GNUNET_TRANSPORT_PS_CONNECTED:
@@ -1243,17 +1186,14 @@ disconnect_neighbour (struct NeighbourMapEntry *n)
     /* we are currently connected, need to send disconnect and do
        internal notifications and update statistics */
     send_disconnect (n);
-    GNUNET_STATISTICS_set (GST_stats,
-                          gettext_noop ("# peers connected"),
-                          --neighbours_connected,
-                          GNUNET_NO);
-    neighbours_disconnect_notification (&n->id);
-    set_state (n, GNUNET_TRANSPORT_PS_DISCONNECT);
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_DISCONNECT,
+                           GNUNET_TIME_UNIT_FOREVER_ABS);
     break;
   case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
     /* Disconnecting while waiting for an ATS address to reconnect,
      * cannot send DISCONNECT */
-    free_neighbour (n, GNUNET_NO);
+    free_neighbour (n);
     return;
   case GNUNET_TRANSPORT_PS_DISCONNECT:
     /* already disconnected, ignore */
@@ -1273,7 +1213,8 @@ disconnect_neighbour (struct NeighbourMapEntry *n)
   if (NULL != n->task)
     GNUNET_SCHEDULER_cancel (n->task);
   n->task = GNUNET_SCHEDULER_add_delayed (DISCONNECT_SENT_TIMEOUT,
-                                         &master_task, n);
+                                         &master_task,
+                                          n);
 }
 
 
@@ -1289,13 +1230,20 @@ disconnect_neighbour (struct NeighbourMapEntry *n)
 static void
 transmit_send_continuation (void *cls,
                             const struct GNUNET_PeerIdentity *receiver,
-                            int success, size_t size_payload, size_t physical)
+                            int success,
+                            size_t size_payload,
+                            size_t physical)
 {
   struct MessageQueue *mq = cls;
   struct NeighbourMapEntry *n;
 
   if (NULL == (n = lookup_neighbour (receiver)))
   {
+    if (NULL != mq->cont)
+      mq->cont (mq->cont_cls,
+                GNUNET_SYSERR /* not connected */,
+                size_payload,
+                0);
     GNUNET_free (mq);
     return; /* disconnect or other error while transmitting, can happen */
   }
@@ -1312,13 +1260,14 @@ transmit_send_continuation (void *cls,
   {
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                 "Bytes_in_send_queue `%u', Message_size %u, result: %s, payload %u, on wire %u\n",
-                bytes_in_send_queue, mq->message_buf_size,
+                bytes_in_send_queue,
+                mq->message_buf_size,
                 (GNUNET_OK == success) ? "OK" : "FAIL",
-                size_payload, physical);
+                size_payload,
+                physical);
     GNUNET_break (0);
   }
 
-
   GNUNET_break (size_payload == mq->message_buf_size);
   bytes_in_send_queue -= mq->message_buf_size;
   GNUNET_STATISTICS_set (GST_stats,
@@ -1390,28 +1339,38 @@ try_transmission_to_peer (struct NeighbourMapEntry *n)
     if (timeout.rel_value_us > 0)
       break;
     GNUNET_STATISTICS_update (GST_stats,
-                             gettext_noop
-                             ("# messages timed out while in transport queue"),
-                             1, GNUNET_NO);
-    GNUNET_CONTAINER_DLL_remove (n->messages_head, n->messages_tail, mq);
+                             gettext_noop ("# messages timed out while in transport queue"),
+                             1,
+                              GNUNET_NO);
+    GNUNET_CONTAINER_DLL_remove (n->messages_head,
+                                 n->messages_tail,
+                                 mq);
     n->is_active = mq;
-    transmit_send_continuation (mq, &n->id,
+    transmit_send_continuation (mq,
+                                &n->id,
                                 GNUNET_SYSERR,
-                                mq->message_buf_size, 0);     /* timeout */
+                                mq->message_buf_size,
+                                0);     /* timeout */
   }
   if (NULL == mq)
     return;                     /* no more messages */
-  GNUNET_CONTAINER_DLL_remove (n->messages_head, n->messages_tail, mq);
+  GNUNET_CONTAINER_DLL_remove (n->messages_head,
+                               n->messages_tail,
+                               mq);
   n->is_active = mq;
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-      "Giving message with %u bytes to plugin session %p\n",
-      mq->message_buf_size, n->primary_address.session);
-
+              "Giving message with %u bytes to plugin session %p\n",
+              mq->message_buf_size,
+              n->primary_address.session);
   (void) send_with_session (n,
-                           mq->message_buf, mq->message_buf_size,
-                           0 /* priority */, timeout, GNUNET_NO,
-                           &transmit_send_continuation, mq);
+                           mq->message_buf,
+                            mq->message_buf_size,
+                           0 /* priority */,
+                            timeout,
+                            GNUNET_NO,
+                           &transmit_send_continuation,
+                            mq);
 }
 
 
@@ -1431,34 +1390,38 @@ send_keepalive (struct NeighbourMapEntry *n)
   uint32_t nonce;
 
   GNUNET_assert ((GNUNET_TRANSPORT_PS_CONNECTED == n->state) ||
-                 (GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT));
+                 (GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT == n->state));
   if (GNUNET_TIME_absolute_get_remaining (n->keep_alive_time).rel_value_us > 0)
     return; /* no keepalive needed at this time */
 
   nonce = 0; /* 0 indicates 'not set' */
   while (0 == nonce)
-    nonce = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE, UINT32_MAX);
+    nonce = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_NONCE,
+                                      UINT32_MAX);
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-      "Sending keep alive to peer `%s' with nonce %u\n",
-      GNUNET_i2s (&n->id), nonce);
-
+              "Sending KEEPALIVE to peer `%s' with nonce %u\n",
+              GNUNET_i2s (&n->id),
+              nonce);
   m.header.size = htons (sizeof (struct SessionKeepAliveMessage));
   m.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_KEEPALIVE);
   m.nonce = htonl (nonce);
 
   timeout = send_with_session (n,
-                              (const void *) &m, sizeof (m),
+                              &m,
+                               sizeof (m),
                               UINT32_MAX /* priority */,
-                              GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES,
+                              GNUNET_TIME_UNIT_FOREVER_REL,
+                               GNUNET_YES,
                               NULL, NULL);
-  GNUNET_STATISTICS_update (GST_stats, gettext_noop ("# keepalives sent"), 1,
+  GNUNET_STATISTICS_update (GST_stats,
+                            gettext_noop ("# KEEPALIVES sent"),
+                            1,
                            GNUNET_NO);
   n->primary_address.keep_alive_nonce = nonce;
   n->expect_latency_response = GNUNET_YES;
   n->last_keep_alive_time = GNUNET_TIME_absolute_get ();
   n->keep_alive_time = GNUNET_TIME_relative_to_absolute (timeout);
-
 }
 
 
@@ -1478,9 +1441,12 @@ GST_neighbours_keepalive (const struct GNUNET_PeerIdentity *neighbour,
   struct SessionKeepAliveMessage msg;
 
   if (sizeof (struct SessionKeepAliveMessage) != ntohs (m->size))
+  {
+    GNUNET_break_op (0);
     return;
+  }
 
-  msg_in = (struct SessionKeepAliveMessage *) m;
+  msg_in = (const struct SessionKeepAliveMessage *) m;
   if (NULL == (n = lookup_neighbour (neighbour)))
   {
     GNUNET_STATISTICS_update (GST_stats,
@@ -1499,18 +1465,25 @@ GST_neighbours_keepalive (const struct GNUNET_PeerIdentity *neighbour,
   }
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-      "Received keep alive request from peer `%s' with nonce %u\n",
-      GNUNET_i2s (&n->id), ntohl (msg_in->nonce));
+              "Received KEEPALIVE request from peer `%s' with nonce %u\n",
+              GNUNET_i2s (&n->id),
+              ntohl (msg_in->nonce));
+  GNUNET_STATISTICS_update (GST_stats,
+                            gettext_noop ("# KEEPALIVES received in good order"),
+                            1,
+                           GNUNET_NO);
 
   /* send reply to allow neighbour to measure latency */
   msg.header.size = htons (sizeof (struct SessionKeepAliveMessage));
   msg.header.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_KEEPALIVE_RESPONSE);
   msg.nonce = msg_in->nonce;
-  (void) send_with_session(n,
-                          (const void *) &msg, sizeof (struct SessionKeepAliveMessage),
-                          UINT32_MAX /* priority */,
-                          GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_YES,
-                          NULL, NULL);
+  (void) send_with_session (n,
+                            &msg,
+                            sizeof (struct SessionKeepAliveMessage),
+                            UINT32_MAX /* priority */,
+                            GNUNET_TIME_UNIT_FOREVER_REL,
+                            GNUNET_YES,
+                            NULL, NULL);
 }
 
 
@@ -1529,61 +1502,70 @@ GST_neighbours_keepalive_response (const struct GNUNET_PeerIdentity *neighbour,
   struct NeighbourMapEntry *n;
   const struct SessionKeepAliveMessage *msg;
   struct GNUNET_TRANSPORT_PluginFunctions *papi;
-  uint32_t latency;
-  struct GNUNET_ATS_Information ats;
+  struct GNUNET_TIME_Relative latency;
 
   if (sizeof (struct SessionKeepAliveMessage) != ntohs (m->size))
+  {
+    GNUNET_break_op (0);
     return;
+  }
 
   msg = (const struct SessionKeepAliveMessage *) m;
   if (NULL == (n = lookup_neighbour (neighbour)))
   {
     GNUNET_STATISTICS_update (GST_stats,
-                              gettext_noop
-                              ("# KEEPALIVE_RESPONSE messages discarded (not connected)"),
-                              1, GNUNET_NO);
+                              gettext_noop ("# KEEPALIVE_RESPONSEs discarded (not connected)"),
+                              1,
+                              GNUNET_NO);
     return;
   }
   if ( (GNUNET_TRANSPORT_PS_CONNECTED != n->state) ||
        (GNUNET_YES != n->expect_latency_response) )
   {
     GNUNET_STATISTICS_update (GST_stats,
-                              gettext_noop
-                              ("# KEEPALIVE_RESPONSE messages discarded (not expected)"),
-                              1, GNUNET_NO);
+                              gettext_noop ("# KEEPALIVE_RESPONSEs discarded (not expected)"),
+                              1,
+                              GNUNET_NO);
     return;
   }
   if (NULL == n->primary_address.address)
   {
     GNUNET_STATISTICS_update (GST_stats,
-                              gettext_noop
-                              ("# KEEPALIVE_RESPONSE messages discarded (address changed)"),
-                              1, GNUNET_NO);
+                              gettext_noop ("# KEEPALIVE_RESPONSEs discarded (address changed)"),
+                              1,
+                              GNUNET_NO);
     return;
   }
   if (n->primary_address.keep_alive_nonce != ntohl (msg->nonce))
   {
-    GNUNET_STATISTICS_update (GST_stats,
-                              gettext_noop
-                              ("# KEEPALIVE_RESPONSE messages discarded (wrong nonce)"),
-                              1, GNUNET_NO);
+    if (0 == n->primary_address.keep_alive_nonce)
+      GNUNET_STATISTICS_update (GST_stats,
+                                gettext_noop ("# KEEPALIVE_RESPONSEs discarded (no nonce)"),
+                                1,
+                                GNUNET_NO);
+    else
+      GNUNET_STATISTICS_update (GST_stats,
+                                gettext_noop ("# KEEPALIVE_RESPONSEs discarded (bad nonce)"),
+                                1,
+                                GNUNET_NO);
     return;
   }
-  else
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-        "Received keep alive response from peer `%s' for session %p\n",
-        GNUNET_i2s (&n->id), n->primary_address.session);
+  GNUNET_STATISTICS_update (GST_stats,
+                            gettext_noop ("# KEEPALIVE_RESPONSEs received (OK)"),
+                            1,
+                            GNUNET_NO);
 
-  }
 
   /* Update session timeout here */
   if (NULL != (papi = GST_plugins_find (n->primary_address.address->transport_name)))
   {
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-        "Updating session for peer `%s' for session %p\n",
-        GNUNET_i2s (&n->id), n->primary_address.session);
-    papi->update_session_timeout (papi->cls, &n->id, n->primary_address.session);
+                "Updating session for peer `%s' for session %p\n",
+                GNUNET_i2s (&n->id),
+                n->primary_address.session);
+    papi->update_session_timeout (papi->cls,
+                                  &n->id,
+                                  n->primary_address.session);
   }
   else
   {
@@ -1592,24 +1574,19 @@ GST_neighbours_keepalive_response (const struct GNUNET_PeerIdentity *neighbour,
 
   n->primary_address.keep_alive_nonce = 0;
   n->expect_latency_response = GNUNET_NO;
-  n->latency = GNUNET_TIME_absolute_get_duration (n->last_keep_alive_time);
-  set_timeout (n, GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
+  set_state_and_timeout (n,
+                         n->state,
+                         GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
 
+  latency = GNUNET_TIME_absolute_get_duration (n->last_keep_alive_time);
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "Latency for peer `%s' is %s\n",
+              "Received KEEPALIVE_RESPONSE from peer `%s', latency is %s\n",
               GNUNET_i2s (&n->id),
-             GNUNET_STRINGS_relative_time_to_string (n->latency,
+             GNUNET_STRINGS_relative_time_to_string (latency,
                                                      GNUNET_YES));
-  /* append latency */
-  ats.type = htonl (GNUNET_ATS_QUALITY_NET_DELAY);
-  if (n->latency.rel_value_us > UINT32_MAX)
-    latency = UINT32_MAX;
-  else
-    latency = n->latency.rel_value_us;
-  ats.value = htonl (latency);
-  GST_ats_update_metrics (n->primary_address.address,
-                          n->primary_address.session,
-                          &ats, 1);
+  GST_ats_update_delay (n->primary_address.address,
+                        GNUNET_TIME_relative_divide (latency,
+                                                     2));
 }
 
 
@@ -1626,8 +1603,9 @@ GST_neighbours_keepalive_response (const struct GNUNET_PeerIdentity *neighbour,
  * @return how long to wait before reading more from this sender
  */
 struct GNUNET_TIME_Relative
-GST_neighbours_calculate_receive_delay (const struct GNUNET_PeerIdentity
-                                        *sender, ssize_t size, int *do_forward)
+GST_neighbours_calculate_receive_delay (const struct GNUNET_PeerIdentity *sender,
+                                        ssize_t size,
+                                        int *do_forward)
 {
   struct NeighbourMapEntry *n;
   struct GNUNET_TIME_Relative ret;
@@ -1688,9 +1666,8 @@ GST_neighbours_calculate_receive_delay (const struct GNUNET_PeerIdentity
   if (ret.rel_value_us > 0)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "Throttling read (%llu bytes excess at %u b/s), waiting %s before reading more.\n",
-                (unsigned long long) n->in_tracker.
-                consumption_since_last_update__,
+                "Throttling read (%lld bytes excess at %u b/s), waiting %s before reading more.\n",
+                (long long) n->in_tracker.consumption_since_last_update__,
                 (unsigned int) n->in_tracker.available_bytes_per_s__,
                 GNUNET_STRINGS_relative_time_to_string (ret, GNUNET_YES));
     GNUNET_STATISTICS_update (GST_stats,
@@ -1710,12 +1687,15 @@ GST_neighbours_calculate_receive_delay (const struct GNUNET_PeerIdentity
  * @param msg_size number of bytes in msg
  * @param timeout when to fail with timeout
  * @param cont function to call when done
- * @param cont_cls closure for 'cont'
+ * @param cont_cls closure for @a cont
  */
 void
-GST_neighbours_send (const struct GNUNET_PeerIdentity *target, const void *msg,
-                     size_t msg_size, struct GNUNET_TIME_Relative timeout,
-                     GST_NeighbourSendContinuation cont, void *cont_cls)
+GST_neighbours_send (const struct GNUNET_PeerIdentity *target,
+                     const void *msg,
+                     size_t msg_size,
+                     struct GNUNET_TIME_Relative timeout,
+                     GST_NeighbourSendContinuation cont,
+                     void *cont_cls)
 {
   struct NeighbourMapEntry *n;
   struct MessageQueue *mq;
@@ -1726,14 +1706,20 @@ GST_neighbours_send (const struct GNUNET_PeerIdentity *target, const void *msg,
   {
     GNUNET_break (0);
     if (NULL != cont)
-      cont (cont_cls, GNUNET_SYSERR, msg_size, 0);
+      cont (cont_cls,
+            GNUNET_SYSERR,
+            msg_size,
+            0);
     return;
   }
   if (GNUNET_YES != test_connected (n))
   {
     GNUNET_break (0);
     if (NULL != cont)
-      cont (cont_cls, GNUNET_SYSERR, msg_size, 0);
+      cont (cont_cls,
+            GNUNET_SYSERR,
+            msg_size,
+            0);
     return;
   }
   bytes_in_send_queue += msg_size;
@@ -1749,22 +1735,37 @@ GST_neighbours_send (const struct GNUNET_PeerIdentity *target, const void *msg,
   mq->message_buf_size = msg_size;
   mq->timeout = GNUNET_TIME_relative_to_absolute (timeout);
 
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Enqueueing %u bytes to send to peer %s\n",
-      msg_size, GNUNET_i2s (target));
-
-  GNUNET_CONTAINER_DLL_insert_tail (n->messages_head, n->messages_tail, mq);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Enqueueing %u bytes to send to peer %s\n",
+              msg_size,
+              GNUNET_i2s (target));
+  GNUNET_CONTAINER_DLL_insert_tail (n->messages_head,
+                                    n->messages_tail,
+                                    mq);
   if (NULL != n->task)
     GNUNET_SCHEDULER_cancel (n->task);
   n->task = GNUNET_SCHEDULER_add_now (&master_task, n);
 }
 
 
+/**
+ * Continuation called from our attempt to transmitted our
+ * #GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_SYN to the specified @a
+ * target.  Continue processing based on the @a result.  Specifically,
+ * if we failed to transmit, discard the address we used.
+ *
+ * @param cls NULL
+ * @param target which peer received the transmission
+ * @param result #GNUNET_OK if sending worked
+ * @param size_payload how many bytes of payload were sent (ignored)
+ * @param size_on_wire how much bandwidth was consumed on the wire (ignored)
+ */
 static void
-send_session_connect_cont (void *cls,
-                           const struct GNUNET_PeerIdentity *target,
-                           int result,
-                           size_t size_payload,
-                           size_t size_on_wire)
+send_session_syn_cont (void *cls,
+                       const struct GNUNET_PeerIdentity *target,
+                       int result,
+                       size_t size_payload,
+                       size_t size_on_wire)
 {
   struct NeighbourMapEntry *n;
 
@@ -1790,38 +1791,43 @@ send_session_connect_cont (void *cls,
     return;
 
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              _("Failed to send SYN message to peer `%s' using address `%s' session %p\n"),
-              GNUNET_i2s (target),
-              GST_plugins_a2s (n->primary_address.address),
-              n->primary_address.session);
-
+              _("Failed to send SYN message to peer `%s'\n"),
+              GNUNET_i2s (target));
   switch (n->state) {
   case GNUNET_TRANSPORT_PS_SYN_SENT:
-    /* Remove address and request and additional one */
+    /* Remove address and request an additional one */
     unset_primary_address (n);
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_INIT_ATS,
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_INIT_ATS,
                            GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
     break;
   case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
-    /* Remove address and request and additional one */
+    /* Remove address and request an additional one */
     unset_primary_address (n);
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_RECONNECT_ATS,
-        GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_RECONNECT_ATS,
+                           GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
     break;
   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
     /* Remove address and request and go back to primary address */
-    GNUNET_STATISTICS_update (GST_stats, gettext_noop
-        ("# Failed attempts to switch addresses (failed to send SYN CONT)"), 1, GNUNET_NO);
-    unset_alternative_address (n);
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_CONNECTED,
-        GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
-    break;
-  default:
-    disconnect_neighbour (n);
-    break;
+    GNUNET_STATISTICS_update (GST_stats,
+                              gettext_noop ("# Failed attempts to switch addresses (failed to send SYN CONT)"),
+                              1,
+                              GNUNET_NO);
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Switch failed, cleaning up alternative address\n");
+    free_address (&n->alternative_address);
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_CONNECTED,
+                           GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
+    break;
+  default:
+    disconnect_neighbour (n);
+    break;
   }
 }
 
+
 /**
  * Send a SYN message via the given address.
  *
@@ -1834,24 +1840,14 @@ send_syn (struct NeighbourAddress *na)
   struct TransportSynMessage connect_msg;
   struct NeighbourMapEntry *n;
 
+  GNUNET_assert (NULL != na->session);
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              "Sending SYN message to peer `%s'\n",
-              GNUNET_i2s (&na->address->peer));
+              "Sending SYN message to peer `%s' at %s\n",
+              GNUNET_i2s (&na->address->peer),
+              GST_plugins_a2s (na->address));
 
-  if (NULL == (papi = GST_plugins_find (na->address->transport_name)))
-  {
-    GNUNET_break (0);
-    return;
-  }
-  if (NULL == na->session)
-    na->session = papi->get_session (papi->cls, na->address);
-  if (NULL == na->session)
-  {
-    GNUNET_break (0);
-    return;
-  }
-  GST_ats_new_session (na->address,
-                       na->session);
+  papi = GST_plugins_find (na->address->transport_name);
+  GNUNET_assert (NULL != papi);
   GNUNET_STATISTICS_update (GST_stats,
                             gettext_noop
                             ("# SYN messages sent"),
@@ -1864,49 +1860,60 @@ send_syn (struct NeighbourAddress *na)
   if (-1 ==
       papi->send (papi->cls,
                   na->session,
-                  (const char *) &connect_msg, sizeof (struct TransportSynMessage),
+                  (const char *) &connect_msg,
+                  sizeof (struct TransportSynMessage),
                   UINT_MAX,
                   SETUP_CONNECTION_TIMEOUT,
-                  send_session_connect_cont, NULL))
+                  &send_session_syn_cont, NULL))
   {
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                _("Failed to transmit SYN message via plugin to %s\n"),
+                _("Failed to transmit SYN message to %s\n"),
                 GST_plugins_a2s (na->address));
-
     n = lookup_neighbour (&na->address->peer);
     if (NULL == n)
     {
       GNUNET_break (0);
       return;
     }
-
     switch (n->state) {
       case GNUNET_TRANSPORT_PS_SYN_SENT:
         /* Remove address and request and additional one */
+        GNUNET_assert (na == &n->primary_address);
         unset_primary_address (n);
-        set_state_and_timeout (n, GNUNET_TRANSPORT_PS_INIT_ATS,
-          GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
+        set_state_and_timeout (n,
+                               GNUNET_TRANSPORT_PS_INIT_ATS,
+                               GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
         /* Hard failure to send the SYN message with this address:
            Destroy address and session */
         break;
       case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
-        /* Remove address and request and additional one */
+        /* Remove address and request an additional one */
+        GNUNET_assert (na == &n->primary_address);
         unset_primary_address (n);
-        set_state_and_timeout (n, GNUNET_TRANSPORT_PS_RECONNECT_ATS,
-          GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
+        set_state_and_timeout (n,
+                               GNUNET_TRANSPORT_PS_RECONNECT_ATS,
+                               GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
         break;
       case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
-        GNUNET_STATISTICS_update (GST_stats, gettext_noop
-            ("# Failed attempts to switch addresses (failed to send SYN)"), 1, GNUNET_NO);
-        /* Remove address and request and additional one */
-        unset_alternative_address (n);
-        set_state_and_timeout (n, GNUNET_TRANSPORT_PS_CONNECTED,
-          GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
+        GNUNET_assert (na == &n->alternative_address);
+        GNUNET_STATISTICS_update (GST_stats,
+                                  gettext_noop ("# Failed attempts to switch addresses (failed to send SYN)"),
+                                  1,
+                                  GNUNET_NO);
+        /* Remove address and request an additional one */
+        GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                    "Switch failed, cleaning up alternative address\n");
+        free_address (&n->alternative_address);
+        set_state_and_timeout (n,
+                               GNUNET_TRANSPORT_PS_CONNECTED,
+                               GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
         break;
       default:
+        GNUNET_break (0);
         disconnect_neighbour (n);
         break;
     }
+    return;
   }
   GST_neighbours_notify_data_sent (na->address,
                                    na->session,
@@ -1914,12 +1921,24 @@ send_syn (struct NeighbourAddress *na)
 }
 
 
+/**
+ * Continuation called from our attempt to transmitted our
+ * #GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_SYN_ACK to the specified @a
+ * target.  Continue processing based on the @a result.  Specifically,
+ * if we failed to transmit, discard the address we used.
+ *
+ * @param cls NULL
+ * @param target which peer received the transmission
+ * @param result #GNUNET_OK if sending worked
+ * @param size_payload how many bytes of payload were sent (ignored)
+ * @param size_on_wire how much bandwidth was consumed on the wire (ignored)
+ */
 static void
-send_session_connect_ack_cont (void *cls,
-                      const struct GNUNET_PeerIdentity *target,
-                      int result,
-                      size_t size_payload,
-                      size_t size_on_wire)
+send_session_syn_ack_cont (void *cls,
+                           const struct GNUNET_PeerIdentity *target,
+                           int result,
+                           size_t size_payload,
+                           size_t size_on_wire)
 {
   struct NeighbourMapEntry *n;
 
@@ -1943,33 +1962,35 @@ send_session_connect_ack_cont (void *cls,
     return;
 
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-            _("Failed to send SYN_ACK message to peer `%s' using address `%s' session %p\n"),
+            _("Failed to send SYN_ACK message to peer `%s' using address `%s'\n"),
             GNUNET_i2s (target),
-            GST_plugins_a2s (n->primary_address.address),
-            n->primary_address.session);
+            GST_plugins_a2s (n->primary_address.address));
 
   /* Remove address and request and additional one */
+  /* FIXME: what if the neighbour's primary address
+     changed in the meantime? Might want to instead
+     pass "something" around in closure to be sure. */
   unset_primary_address (n);
   n->ack_state = ACK_SEND_SYN_ACK;
-  set_state_and_timeout (n, GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
-      GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
-  return;
+  set_state_and_timeout (n,
+                         GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
+                         GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
 }
 
 
 /**
  * Send a SYN_ACK message via the given address.
  *
- * @param address address to use
- * @param session session to use
+ * @param na address and session to use
  * @param timestamp timestamp to use for the ACK message
- * @return GNUNET_SYSERR if sending immediately failed, GNUNET_OK otherwise
+ * @return #GNUNET_SYSERR if sending immediately failed, #GNUNET_OK otherwise
  */
 static void
-send_connect_ack_message (const struct GNUNET_HELLO_Address *address,
-                         struct Session *session,
-                         struct GNUNET_TIME_Absolute timestamp)
+send_syn_ack_message (struct NeighbourAddress *na,
+                      struct GNUNET_TIME_Absolute timestamp)
 {
+  const struct GNUNET_HELLO_Address *address = na->address;
+  struct Session *session = na->session;
   struct GNUNET_TRANSPORT_PluginFunctions *papi;
   struct TransportSynMessage connect_msg;
   struct NeighbourMapEntry *n;
@@ -1984,13 +2005,15 @@ send_connect_ack_message (const struct GNUNET_HELLO_Address *address,
     return;
   }
   if (NULL == session)
-    session = papi->get_session (papi->cls, address);
+    session = papi->get_session (papi->cls,
+                                 address);
   if (NULL == session)
   {
     GNUNET_break (0);
     return;
   }
-  GST_ats_new_session (address, session);
+  GST_ats_new_session (address,
+                       session);
   GNUNET_STATISTICS_update (GST_stats,
                             gettext_noop
                             ("# SYN_ACK messages sent"),
@@ -2000,15 +2023,17 @@ send_connect_ack_message (const struct GNUNET_HELLO_Address *address,
   connect_msg.reserved = htonl (0);
   connect_msg.timestamp = GNUNET_TIME_absolute_hton (timestamp);
 
-  if (GNUNET_SYSERR == papi->send (papi->cls,
-                    session,
-                    (const char *) &connect_msg, sizeof (struct TransportSynMessage),
-                    UINT_MAX,
-                    GNUNET_TIME_UNIT_FOREVER_REL,
-                    send_session_connect_ack_cont, NULL))
+  if (GNUNET_SYSERR ==
+      papi->send (papi->cls,
+                  session,
+                  (const char *) &connect_msg,
+                  sizeof (struct TransportSynMessage),
+                  UINT_MAX,
+                  GNUNET_TIME_UNIT_FOREVER_REL,
+                  &send_session_syn_ack_cont, NULL))
   {
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                _("Failed to transmit SYN_ACK message via plugin to %s\n"),
+                _("Failed to transmit SYN_ACK message to %s\n"),
                 GST_plugins_a2s (address));
 
     n = lookup_neighbour (&address->peer);
@@ -2020,180 +2045,47 @@ send_connect_ack_message (const struct GNUNET_HELLO_Address *address,
     /* Remove address and request and additional one */
     unset_primary_address (n);
     n->ack_state = ACK_SEND_SYN_ACK;
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
-        GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
+                           GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
     return;
   }
-
 }
 
-struct QuotaNotificationRequest
-{
-  struct GNUNET_PeerIdentity peer;
-  struct Session *session;
-  char *plugin;
-};
-
-struct QNR_LookContext
-{
-  struct GNUNET_PeerIdentity peer;
-  struct Session *session;
-  const char *plugin;
 
-  struct QuotaNotificationRequest *res;
-};
-
-static int
-find_notification_request (void *cls, const struct GNUNET_PeerIdentity *key, void *value)
-{
-  struct QNR_LookContext *qnr_ctx = cls;
-  struct QuotaNotificationRequest *qnr = value;
-
-  if ((qnr->session == qnr_ctx->session) &&
-      (0 == memcmp (&qnr->peer,
-                    &qnr_ctx->peer,
-                    sizeof (struct GNUNET_PeerIdentity))) &&
-      (0 == strcmp(qnr_ctx->plugin, qnr->plugin)))
-  {
-    qnr_ctx->res = value;
-    return GNUNET_NO;
-  }
-  return GNUNET_YES;
-}
-
-
-void
-GST_neighbours_register_quota_notification (void *cls,
-                                            const struct GNUNET_PeerIdentity *peer,
-                                            const char *plugin,
-                                            struct Session *session)
-{
-  struct QuotaNotificationRequest *qnr;
-  struct QNR_LookContext qnr_ctx;
-
-  if (NULL == registered_quota_notifications)
-  {
-    return; /* init or shutdown */
-  }
-
-  qnr_ctx.peer = (*peer);
-  qnr_ctx.plugin = plugin;
-  qnr_ctx.session = session;
-  qnr_ctx.res = NULL;
-
-  GNUNET_CONTAINER_multipeermap_get_multiple (registered_quota_notifications,
-      peer, &find_notification_request, &qnr_ctx);
-  if (NULL != qnr_ctx.res)
-  {
-    GNUNET_break(0);
-    return;
-  }
-
-  qnr = GNUNET_new (struct QuotaNotificationRequest);
-  qnr->peer =  (*peer);
-  qnr->plugin = GNUNET_strdup (plugin);
-  qnr->session = session;
-
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-      "Adding notification for peer `%s' plugin `%s' session %p \n",
-      GNUNET_i2s (peer), plugin, session);
-
-  GNUNET_CONTAINER_multipeermap_put (registered_quota_notifications, peer,
-      qnr, GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
-}
-
-
-void
-GST_neighbours_unregister_quota_notification(void *cls,
-                                             const struct GNUNET_PeerIdentity *peer,
-                                             const char *plugin,
-                                             struct Session *session)
-{
-  struct QNR_LookContext qnr_ctx;
-
-  if (NULL == registered_quota_notifications)
-  {
-    return; /* init or shutdown */
-  }
-
-  qnr_ctx.peer = (*peer);
-  qnr_ctx.plugin = plugin;
-  qnr_ctx.session = session;
-  qnr_ctx.res = NULL;
-
-  GNUNET_CONTAINER_multipeermap_iterate (registered_quota_notifications,
-      &find_notification_request, &qnr_ctx);
-  if (NULL == qnr_ctx.res)
-  {
-    GNUNET_break(0);
-    return;
-  }
-
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-      "Removing notification for peer `%s' plugin `%s' session %p \n",
-      GNUNET_i2s (peer), plugin, session);
-
-  GNUNET_CONTAINER_multipeermap_remove (registered_quota_notifications, peer,
-      qnr_ctx.res);
-  GNUNET_free (qnr_ctx.res->plugin);
-  GNUNET_free (qnr_ctx.res);
-}
-
-
-static int
-notification_cb (void *cls,
-                 const struct GNUNET_PeerIdentity *key,
-                 void *value)
+/**
+ * Function called by the bandwidth tracker for a peer whenever
+ * the tracker's state changed such that we need to recalculate
+ * the delay for flow control.  We calculate the latest delay
+ * and inform the plugin (if applicable).
+ *
+ * @param cls the `struct NeighbourMapEntry` to update calculations for
+ */
+static void
+inbound_bw_tracker_update (void *cls)
 {
-  /* struct NeighbourMapEntry *n = cls; */
-  struct QuotaNotificationRequest *qnr = value;
+  struct NeighbourMapEntry *n = cls;
   struct GNUNET_TRANSPORT_PluginFunctions *papi;
   struct GNUNET_TIME_Relative delay;
   int do_forward;
 
-  papi = GST_plugins_find(qnr->plugin);
-  if (NULL == papi)
-  {
-    GNUNET_break (0);
-    return GNUNET_OK;
-  }
-
-  delay = GST_neighbours_calculate_receive_delay (key, 0, &do_forward);
+  if (NULL == n->primary_address.address)
+    return; /* not active, ignore */
+  papi = GST_plugins_find (n->primary_address.address->transport_name);
+  GNUNET_assert (NULL != papi);
+  if (NULL == papi->update_inbound_delay)
+    return;
+  delay = GST_neighbours_calculate_receive_delay (&n->id,
+                                                  0,
+                                                  &do_forward);
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-      "New inbound delay for peer `%s' is %llu ms\n", GNUNET_i2s (key),
-      delay.rel_value_us / 1000);
-
-  if (NULL != papi->update_inbound_delay)
-    papi->update_inbound_delay (papi->cls, key, qnr->session, delay);
-  return GNUNET_OK;
-}
-
-
-static int
-free_notification_cb (void *cls,
-                      const struct GNUNET_PeerIdentity *key,
-                      void *value)
-{
-  /* struct NeighbourMapEntry *n = cls; */
-  struct QuotaNotificationRequest *qnr = value;
-
-  GNUNET_break (GNUNET_OK == GNUNET_CONTAINER_multipeermap_remove (registered_quota_notifications, key,
-      qnr));
-  GNUNET_free(qnr->plugin);
-  GNUNET_free(qnr);
-
-  return GNUNET_OK;
-}
-
-
-static void
-inbound_bw_tracker_update (void *cls)
-{
-  struct NeighbourMapEntry *n = cls;
-
-  /* Quota was updated, tell plugins to update the time to receive next */
-  GNUNET_CONTAINER_multipeermap_get_multiple (registered_quota_notifications,
-      &n->id, &notification_cb, n);
+              "New inbound delay for peer `%s' is %llu ms\n",
+              GNUNET_i2s (&n->id),
+              delay.rel_value_us / 1000);
+  papi->update_inbound_delay (papi->cls,
+                              &n->id,
+                              n->primary_address.session,
+                              delay);
 }
 
 
@@ -2214,62 +2106,54 @@ setup_neighbour (const struct GNUNET_PeerIdentity *peer)
   n = GNUNET_new (struct NeighbourMapEntry);
   n->id = *peer;
   n->ack_state = ACK_UNDEFINED;
-  n->latency = GNUNET_TIME_UNIT_FOREVER_REL;
   n->last_util_transmission = GNUNET_TIME_absolute_get();
-  n->util_payload_bytes_recv = 0;
-  n->util_payload_bytes_sent = 0;
-  n->util_total_bytes_recv = 0;
-  n->util_total_bytes_sent = 0;
-  GNUNET_BANDWIDTH_tracker_init (&n->in_tracker, &inbound_bw_tracker_update, n,
+  GNUNET_BANDWIDTH_tracker_init (&n->in_tracker,
+                                 &inbound_bw_tracker_update,
+                                 n,
                                  GNUNET_CONSTANTS_DEFAULT_BW_IN_OUT,
                                  MAX_BANDWIDTH_CARRY_S);
   n->task = GNUNET_SCHEDULER_add_now (&master_task, n);
-  set_state_and_timeout (n, GNUNET_TRANSPORT_PS_NOT_CONNECTED, GNUNET_TIME_UNIT_FOREVER_ABS);
+  set_state_and_timeout (n,
+                         GNUNET_TRANSPORT_PS_NOT_CONNECTED,
+                         GNUNET_TIME_UNIT_FOREVER_ABS);
   GNUNET_assert (GNUNET_OK ==
                  GNUNET_CONTAINER_multipeermap_put (neighbours,
                                                     &n->id, n,
                                                     GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
+  n->suggest_handle = GNUNET_ATS_connectivity_suggest (GST_ats_connect,
+                                                       peer);
+
   return n;
 }
 
 
 /**
- * FIXME
+ * Entry in a DLL we use to keep track of pending blacklist checks.
  */
 struct BlacklistCheckSwitchContext
 {
   /**
-   * FIXME
+   * DLL prev pointer.
    */
   struct BlacklistCheckSwitchContext *prev;
 
   /**
-   * FIXME
+   * DLL next pointer.
    */
   struct BlacklistCheckSwitchContext *next;
 
   /**
-   * FIXME
+   * Handle to the blacklist check we are performing.
    */
   struct GST_BlacklistCheck *blc;
 
   /**
-   * FIXME
-   */
-  struct GNUNET_HELLO_Address *address;
-
-  /**
-   * FIXME
-   */
-  struct Session *session;
-
-  /**
-   * FIXME
+   * Inbound bandwidth that was assigned to @e address.
    */
   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in;
 
   /**
-   * FIXME
+   * Outbound bandwidth that was assigned to @e address.
    */
   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out;
 };
@@ -2281,11 +2165,17 @@ struct BlacklistCheckSwitchContext
  *
  * @param cls blc_ctx bl context
  * @param peer the peer
- * @param result the result
+ * @param address address associated with the request
+ * @param session session associated with the request
+ * @param result #GNUNET_OK if the connection is allowed,
+ *               #GNUNET_NO if not,
+ *               #GNUNET_SYSERR if operation was aborted
  */
 static void
 try_connect_bl_check_cont (void *cls,
                            const struct GNUNET_PeerIdentity *peer,
+                          const struct GNUNET_HELLO_Address *address,
+                          struct Session *session,
                            int result)
 {
   struct BlacklistCheckSwitchContext *blc_ctx = cls;
@@ -2313,14 +2203,9 @@ try_connect_bl_check_cont (void *cls,
   set_state_and_timeout (n,
                          GNUNET_TRANSPORT_PS_INIT_ATS,
                          GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
-  GNUNET_ATS_reset_backoff (GST_ats, peer);
-  GNUNET_assert (NULL == n->suggest_handle);
-  n->suggest_handle = GNUNET_ATS_suggest_address (GST_ats,
-                                                  peer);
 }
 
 
-
 /**
  * Try to create a connection to the given target (eventually).
  *
@@ -2352,7 +2237,7 @@ GST_neighbours_try_connect (const struct GNUNET_PeerIdentity *target)
     case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
       /* this should not be possible */
       GNUNET_break (0);
-      free_neighbour (n, GNUNET_NO);
+      free_neighbour (n);
       break;
     case GNUNET_TRANSPORT_PS_INIT_ATS:
     case GNUNET_TRANSPORT_PS_SYN_SENT:
@@ -2372,7 +2257,7 @@ GST_neighbours_try_connect (const struct GNUNET_PeerIdentity *target)
       return; /* already connected */
     case GNUNET_TRANSPORT_PS_DISCONNECT:
       /* get rid of remains, ready to re-try immediately */
-      free_neighbour (n, GNUNET_NO);
+      free_neighbour (n);
       break;
     case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
       /* should not be possible */
@@ -2383,17 +2268,24 @@ GST_neighbours_try_connect (const struct GNUNET_PeerIdentity *target)
                   "Unhandled state `%s'\n",
                   GNUNET_TRANSPORT_ps2s (n->state));
       GNUNET_break (0);
-      free_neighbour (n, GNUNET_NO);
+      free_neighbour (n);
       break;
     }
   }
 
   /* Do blacklist check if connecting to this peer is allowed */
   blc_ctx = GNUNET_new (struct BlacklistCheckSwitchContext);
-  GNUNET_CONTAINER_DLL_insert (pending_bc_head, pending_bc_tail, blc_ctx);
+  GNUNET_CONTAINER_DLL_insert (pending_bc_head,
+                               pending_bc_tail,
+                               blc_ctx);
 
-  if (NULL != (blc = GST_blacklist_test_allowed (target, NULL,
-        &try_connect_bl_check_cont, blc_ctx)))
+  if (NULL !=
+      (blc = GST_blacklist_test_allowed (target,
+                                         NULL,
+                                         &try_connect_bl_check_cont,
+                                         blc_ctx,
+                                        NULL,
+                                        NULL)))
   {
     blc_ctx->blc = blc;
   }
@@ -2456,16 +2348,16 @@ GST_neighbours_handle_session_syn (const struct GNUNET_MessageHeader *message,
   {
   case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
     /* Request an address from ATS to send SYN_ACK to this peer */
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
-        GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
-    if (NULL == n->suggest_handle)
-      n->suggest_handle = GNUNET_ATS_suggest_address (GST_ats, peer);
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
+                           GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
     break;
   case GNUNET_TRANSPORT_PS_INIT_ATS:
     /* SYN message takes priority over us asking ATS for address:
      * Wait for ATS to suggest an address and send SYN_ACK */
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
-        GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
+                           GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
     break;
   case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
     /* We already wait for an address to send an SYN_ACK */
@@ -2474,16 +2366,16 @@ GST_neighbours_handle_session_syn (const struct GNUNET_MessageHeader *message,
   case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
     /* Send ACK immediately */
     n->ack_state = ACK_SEND_ACK;
-    send_connect_ack_message (n->primary_address.address,
-                              n->primary_address.session, ts);
+    send_syn_ack_message (&n->primary_address,
+                          ts);
     break;
   case GNUNET_TRANSPORT_PS_CONNECTED:
     /* we are already connected and can thus send the ACK immediately */
     GNUNET_assert (NULL != n->primary_address.address);
     GNUNET_assert (NULL != n->primary_address.session);
     n->ack_state = ACK_SEND_ACK;
-    send_connect_ack_message (n->primary_address.address,
-                              n->primary_address.session, ts);
+    send_syn_ack_message (&n->primary_address,
+                          ts);
     break;
   case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
     /* We wait for ATS address suggestion */
@@ -2492,8 +2384,8 @@ GST_neighbours_handle_session_syn (const struct GNUNET_MessageHeader *message,
     /* We received a SYN message while waiting for a SYN_ACK in fast
      * reconnect. Send SYN_ACK immediately */
     n->ack_state = ACK_SEND_ACK;
-    send_connect_ack_message (n->primary_address.address,
-        n->primary_address.session, n->connect_ack_timestamp);
+    send_syn_ack_message (&n->primary_address,
+                          n->connect_ack_timestamp);
     break;
   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
     /* We are already connected and can thus send the ACK immediately;
@@ -2502,20 +2394,20 @@ GST_neighbours_handle_session_syn (const struct GNUNET_MessageHeader *message,
     GNUNET_assert (NULL != n->primary_address.address);
     GNUNET_assert (NULL != n->primary_address.session);
     n->ack_state = ACK_SEND_ACK;
-    send_connect_ack_message (n->primary_address.address,
-        n->primary_address.session, ts);
+    send_syn_ack_message (&n->primary_address,
+                          ts);
     break;
   case GNUNET_TRANSPORT_PS_DISCONNECT:
-    /* Get rid of remains without terminating sessions, ready to re-try */
-    free_neighbour (n, GNUNET_YES);
+    /* Get rid of remains and re-try */
+    free_neighbour (n);
     n = setup_neighbour (peer);
     /* Remember the SYN time stamp for ACK message */
     n->ack_state = ACK_SEND_SYN_ACK;
     n->connect_ack_timestamp = ts;
     /* Request an address for the peer */
-    n->suggest_handle = GNUNET_ATS_suggest_address (GST_ats, peer);
-    GNUNET_ATS_reset_backoff (GST_ats, peer);
-    set_state (n, GNUNET_TRANSPORT_PS_SYN_RECV_ATS);
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_SYN_RECV_ATS,
+                           GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
     break;
   case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
     /* should not be possible */
@@ -2533,174 +2425,224 @@ GST_neighbours_handle_session_syn (const struct GNUNET_MessageHeader *message,
 
 
 /**
- * We've been asked to switch addresses, and just now
- * got the result from the blacklist check to see if this
- * is allowed.
+ * Check if the given @a address is the same that we are already
+ * using for the respective neighbour. If so, update the bandwidth
+ * assignment and possibly the session and return #GNUNET_OK.
+ * If the new address is different from what the neighbour is
+ * using right now, return #GNUNET_NO.
+ *
+ * @param address address of the other peer,
+ * @param session session to use or NULL if transport should initiate a session
+ * @param bandwidth_in inbound quota to be used when connection is up,
+ *     0 to disconnect from peer
+ * @param bandwidth_out outbound quota to be used when connection is up,
+ *     0 to disconnect from peer
+ * @return #GNUNET_OK if we were able to just update the bandwidth and session,
+ *         #GNUNET_NO if more extensive changes are required (address changed)
+ */
+static int
+try_run_fast_ats_update (const struct GNUNET_HELLO_Address *address,
+                         struct Session *session,
+                         struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
+                         struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
+{
+  struct NeighbourMapEntry *n;
+
+  n = lookup_neighbour (&address->peer);
+  if ( (NULL == n) ||
+       (NULL == n->primary_address.address) ||
+       (0 != GNUNET_HELLO_address_cmp (address,
+                                       n->primary_address.address)) )
+    return GNUNET_NO;
+  /* We are not really switching addresses, but merely adjusting
+     session and/or bandwidth, can do fast ATS update! */
+  if (session != n->primary_address.session)
+  {
+    /* switch to a different session, but keeping same address; could
+       happen if there is a 2nd inbound connection */
+    n->primary_address.session = session;
+    GNUNET_assert (GNUNET_YES ==
+                   GST_ats_is_known (n->primary_address.address,
+                                     n->primary_address.session));
+  }
+  n->primary_address.bandwidth_in = bandwidth_in;
+  n->primary_address.bandwidth_out = bandwidth_out;
+  GST_neighbours_set_incoming_quota (&address->peer,
+                                     bandwidth_in);
+  send_outbound_quota (&address->peer,
+                       bandwidth_out);
+  return GNUNET_OK;
+}
+
+
+/**
+ * We've been asked to switch addresses, and just now got the result
+ * from the blacklist check to see if this is allowed.
  *
  * @param cls the `struct BlacklistCheckSwitchContext` with
  *        the information about the future address
  * @param peer the peer we may switch addresses on
- * @param result #GNUNET_NO if we are not allowed to use the new
- *        address
+ * @param address address associated with the request
+ * @param session session associated with the request
+ * @param result #GNUNET_OK if the connection is allowed,
+ *               #GNUNET_NO if not,
+ *               #GNUNET_SYSERR if operation was aborted
  */
 static void
 switch_address_bl_check_cont (void *cls,
                               const struct GNUNET_PeerIdentity *peer,
+                             const struct GNUNET_HELLO_Address *address,
+                             struct Session *session,
                               int result)
 {
   struct BlacklistCheckSwitchContext *blc_ctx = cls;
   struct GNUNET_TRANSPORT_PluginFunctions *papi;
   struct NeighbourMapEntry *n;
 
-  papi = GST_plugins_find (blc_ctx->address->transport_name);
-
-  if ( (NULL == (n = lookup_neighbour (peer))) || (result == GNUNET_NO) ||
-       (NULL == (papi)) )
-  {
-    if (NULL == n)
-    {
-      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                  "Peer %s is unknown, suggestion ignored\n",
-                  GNUNET_i2s (peer));
-    }
-    if (result == GNUNET_NO)
-    {
-      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-          "Blacklist denied to switch to suggested address `%s' session %p for peer `%s'\n",
-          GST_plugins_a2s (blc_ctx->address),
-          blc_ctx->session,
-          GNUNET_i2s (&blc_ctx->address->peer));
-    }
-    if (NULL == papi)
-    {
-      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-          "Plugin `%s' for suggested address `%s' session %p for peer `%s' is not available\n",
-          blc_ctx->address->transport_name,
-          GST_plugins_a2s (blc_ctx->address),
-          blc_ctx->session,
-          GNUNET_i2s (&blc_ctx->address->peer));
-    }
+  if (GNUNET_SYSERR == result)
+    goto cleanup;
 
-    /* This address is blacklisted, delete session */
-    /* FIXME: tell plugin to force killing session here and now! */
+  papi = GST_plugins_find (address->transport_name);
+  GNUNET_assert (NULL != papi);
 
-    /* Remove blacklist check and clean up */
-    GNUNET_CONTAINER_DLL_remove (pending_bc_head,
-                                 pending_bc_tail,
-                                 blc_ctx);
-    GNUNET_HELLO_address_free (blc_ctx->address);
-    GNUNET_free (blc_ctx);
-    return;
+  if (GNUNET_NO == result)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Blacklist denied to switch to suggested address `%s' session %p for peer `%s'\n",
+                GST_plugins_a2s (address),
+               session,
+                GNUNET_i2s (peer));
+    GNUNET_STATISTICS_update (GST_stats,
+                              "# ATS suggestions ignored (blacklist denied)",
+                              1,
+                              GNUNET_NO);
+    papi->disconnect_session (papi->cls,
+                             session);
+    if (GNUNET_YES !=
+       GNUNET_HELLO_address_check_option (address,
+                                          GNUNET_HELLO_ADDRESS_INFO_INBOUND))
+      GST_ats_block_address (address,
+                            NULL);
+    goto cleanup;
   }
 
-  if (NULL == blc_ctx->session)
+
+  if (NULL == session)
   {
-    blc_ctx->session = papi->get_session (papi->cls,
-                                          blc_ctx->address);
+    /* need to create a session, ATS only gave us an address */
+    session = papi->get_session (papi->cls,
+                                address);
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 "Obtained new session for peer `%s' and  address '%s': %p\n",
-                GNUNET_i2s (&blc_ctx->address->peer),
-                GST_plugins_a2s (blc_ctx->address),
-                blc_ctx->session);
-    if (NULL != blc_ctx->session)
-      GST_ats_new_session (blc_ctx->address,
-                           blc_ctx->session);
-
+                GNUNET_i2s (&address->peer),
+                GST_plugins_a2s (address),
+                session);
+    if (NULL != session)
+      GST_ats_new_session (address,
+                           session);
   }
-  if (NULL == blc_ctx->session)
+  if (NULL == session)
   {
+    /* session creation failed, bad!, fail! */
+    GNUNET_STATISTICS_update (GST_stats,
+                              "# ATS suggestions ignored (failed to create session)",
+                              1,
+                              GNUNET_NO);
     /* No session could be obtained, remove blacklist check and clean up */
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "Failed to obtain new session for peer `%s' and  address '%s'\n",
-                GNUNET_i2s (&blc_ctx->address->peer),
-                GST_plugins_a2s (blc_ctx->address));
-    /* Delete address in ATS */
-    GNUNET_CONTAINER_DLL_remove (pending_bc_head,
-                                 pending_bc_tail,
-                                 blc_ctx);
-    GNUNET_HELLO_address_free (blc_ctx->address);
-    GNUNET_free (blc_ctx);
-    return;
-  }
-
-  if ( (NULL != n->primary_address.address) &&
-       (0 == GNUNET_HELLO_address_cmp(blc_ctx->address, n->primary_address.address)) )
+                "Failed to obtain new session for peer `%s' and address '%s'\n",
+                GNUNET_i2s (&address->peer),
+                GST_plugins_a2s (address));
+    GST_ats_block_address (address,
+                           session);
+    goto cleanup;
+  }
+
+  /* We did this check already before going into blacklist, but
+     it is theoretically possible that the situation changed in
+     the meantime, hence we check again here */
+  if (GNUNET_OK ==
+      try_run_fast_ats_update (address,
+                               session,
+                               blc_ctx->bandwidth_in,
+                               blc_ctx->bandwidth_out))
+    goto cleanup; /* was just a minor update, we're done */
+
+  /* check if we also need to setup the neighbour entry */
+  if (NULL == (n = lookup_neighbour (peer)))
   {
-    if (blc_ctx->session == n->primary_address.session)
-    {
-      /* This address is already primary, update only quotas */
-      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-          "Updating quota for peer `%s' address `%s' session %p\n",
-          GNUNET_i2s (&blc_ctx->address->peer),
-          GST_plugins_a2s (blc_ctx->address),
-          blc_ctx->session);
-
-      set_primary_address (n, blc_ctx->address, blc_ctx->session,
-          blc_ctx->bandwidth_in, blc_ctx->bandwidth_out, GNUNET_NO);
-
-      GNUNET_CONTAINER_DLL_remove (pending_bc_head, pending_bc_tail, blc_ctx);
-      GNUNET_HELLO_address_free(blc_ctx->address);
-      GNUNET_free (blc_ctx);
-      return;
-    }
+    n = setup_neighbour (peer);
+    n->state = GNUNET_TRANSPORT_PS_INIT_ATS;
   }
 
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-      "Peer `%s' switches to address `%s' session %p\n",
-      GNUNET_i2s (&blc_ctx->address->peer),
-      GST_plugins_a2s (blc_ctx->address),
-      blc_ctx->session);
+              "Peer `%s' switches to address `%s'\n",
+              GNUNET_i2s (&address->peer),
+              GST_plugins_a2s (address));
 
   switch (n->state)
   {
   case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
     GNUNET_break (0);
-    free_neighbour (n, GNUNET_NO);
+    GST_ats_block_address (address,
+                           session);
+    free_neighbour (n);
     return;
   case GNUNET_TRANSPORT_PS_INIT_ATS:
     /* We requested an address and ATS suggests one:
      * set primary address and send SYN message*/
-    set_primary_address (n, blc_ctx->address, blc_ctx->session,
-        blc_ctx->bandwidth_in, blc_ctx->bandwidth_out, GNUNET_NO);
-    if ( (ACK_SEND_SYN_ACK == n->ack_state) )
+    set_primary_address (n,
+                         address,
+                         session,
+                         blc_ctx->bandwidth_in,
+                         blc_ctx->bandwidth_out);
+    if (ACK_SEND_SYN_ACK == n->ack_state)
     {
       /* Send pending SYN_ACK message */
       n->ack_state = ACK_SEND_ACK;
-      send_connect_ack_message (n->primary_address.address,
-          n->primary_address.session, n->connect_ack_timestamp);
+      send_syn_ack_message (&n->primary_address,
+                            n->connect_ack_timestamp);
     }
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_SYN_SENT,
-        GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_SYN_SENT,
+                           GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
     send_syn (&n->primary_address);
     break;
   case GNUNET_TRANSPORT_PS_SYN_SENT:
     /* ATS suggested a new address while waiting for an SYN_ACK:
      * Switch and send new SYN */
     /* ATS suggests a different address, switch again */
-    set_primary_address (n, blc_ctx->address, blc_ctx->session,
-        blc_ctx->bandwidth_in, blc_ctx->bandwidth_out, GNUNET_NO);
+    set_primary_address (n,
+                         address,
+                         session,
+                         blc_ctx->bandwidth_in,
+                         blc_ctx->bandwidth_out);
     if (ACK_SEND_SYN_ACK == n->ack_state)
     {
       /* Send pending SYN_ACK message */
       n->ack_state = ACK_SEND_ACK;
-      send_connect_ack_message (n->primary_address.address,
-          n->primary_address.session, n->connect_ack_timestamp);
+      send_syn_ack_message (&n->primary_address,
+                            n->connect_ack_timestamp);
     }
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_SYN_SENT,
-        GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_SYN_SENT,
+                           GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
     send_syn (&n->primary_address);
     break;
   case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
     /* We requested an address and ATS suggests one:
      * set primary address and send SYN_ACK message*/
-    set_primary_address (n, blc_ctx->address, blc_ctx->session,
-        blc_ctx->bandwidth_in, blc_ctx->bandwidth_out, GNUNET_NO);
+    set_primary_address (n,
+                         address,
+                         session,
+                         blc_ctx->bandwidth_in,
+                         blc_ctx->bandwidth_out);
     /* Send an ACK message as a response to the SYN msg */
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_SYN_RECV_ACK,
-        GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
-    send_connect_ack_message (n->primary_address.address,
-                              n->primary_address.session,
-                              n->connect_ack_timestamp);
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_SYN_RECV_ACK,
+                           GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
+    send_syn_ack_message (&n->primary_address,
+                          n->connect_ack_timestamp);
     if ( (ACK_SEND_SYN_ACK == n->ack_state) ||
          (ACK_UNDEFINED == n->ack_state) )
       n->ack_state = ACK_SEND_ACK;
@@ -2711,75 +2653,100 @@ switch_address_bl_check_cont (void *cls,
     if ( (ACK_SEND_SYN_ACK == n->ack_state) )
     {
       n->ack_state = ACK_SEND_ACK;
-      send_connect_ack_message (n->primary_address.address,
-          n->primary_address.session, n->connect_ack_timestamp);
+      send_syn_ack_message (&n->primary_address,
+                            n->connect_ack_timestamp);
     }
-    set_primary_address (n, blc_ctx->address, blc_ctx->session,
-        blc_ctx->bandwidth_in, blc_ctx->bandwidth_out, GNUNET_NO);
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_SYN_RECV_ACK,
-        GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
+    set_primary_address (n,
+                        address,
+                         session,
+                         blc_ctx->bandwidth_in,
+                         blc_ctx->bandwidth_out);
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_SYN_RECV_ACK,
+                           GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
     break;
   case GNUNET_TRANSPORT_PS_CONNECTED:
     GNUNET_assert (NULL != n->primary_address.address);
     GNUNET_assert (NULL != n->primary_address.session);
-    if (n->primary_address.session == blc_ctx->session)
-    {
-      /* not an address change, just a quota change */
-      set_primary_address (n, blc_ctx->address, blc_ctx->session,
-          blc_ctx->bandwidth_in, blc_ctx->bandwidth_out, GNUNET_YES);
-      break;
-    }
+    GNUNET_break (n->primary_address.session != session);
     /* ATS asks us to switch a life connection; see if we can get
        a SYN_ACK on it before we actually do this! */
-    set_alternative_address (n, blc_ctx->address, blc_ctx->session,
-        blc_ctx->bandwidth_in, blc_ctx->bandwidth_out);
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT,
-        GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
-    GNUNET_STATISTICS_update (GST_stats, gettext_noop
-        ("# Attempts to switch addresses"), 1, GNUNET_NO);
+    set_alternative_address (n,
+                             address,
+                             session,
+                             blc_ctx->bandwidth_in,
+                             blc_ctx->bandwidth_out);
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT,
+                           GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
+    GNUNET_STATISTICS_update (GST_stats,
+                              gettext_noop ("# Attempts to switch addresses"),
+                              1,
+                              GNUNET_NO);
     send_syn (&n->alternative_address);
     break;
   case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
-    set_primary_address (n, blc_ctx->address, blc_ctx->session,
-        blc_ctx->bandwidth_in, blc_ctx->bandwidth_out, GNUNET_NO);
-    if ( (ACK_SEND_SYN_ACK == n->ack_state) )
+    set_primary_address (n,
+                         address,
+                         session,
+                         blc_ctx->bandwidth_in,
+                         blc_ctx->bandwidth_out);
+    if (ACK_SEND_SYN_ACK == n->ack_state)
     {
       /* Send pending SYN_ACK message */
       n->ack_state = ACK_SEND_ACK;
-      send_connect_ack_message (n->primary_address.address,
-          n->primary_address.session, n->connect_ack_timestamp);
+      send_syn_ack_message (&n->primary_address,
+                            n->connect_ack_timestamp);
     }
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_RECONNECT_SENT,
-        GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_RECONNECT_SENT,
+                           GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
     send_syn (&n->primary_address);
     break;
   case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
     /* ATS asks us to switch while we were trying to reconnect; switch to new
        address and send SYN again */
-    set_primary_address (n, blc_ctx->address, blc_ctx->session,
-        blc_ctx->bandwidth_in, blc_ctx->bandwidth_out, GNUNET_NO);
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_RECONNECT_SENT,
-        GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
+    set_primary_address (n,
+                         address,
+                         session,
+                         blc_ctx->bandwidth_in,
+                         blc_ctx->bandwidth_out);
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_RECONNECT_SENT,
+                           GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
     send_syn (&n->primary_address);
     break;
   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
-    if ( (0 == GNUNET_HELLO_address_cmp(n->primary_address.address,
-        blc_ctx->address) && n->primary_address.session == blc_ctx->session) )
+    if ( (0 == GNUNET_HELLO_address_cmp (n->primary_address.address,
+                                         address)) &&
+         (n->primary_address.session == session) )
     {
       /* ATS switches back to still-active session */
+      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                  "ATS double-switched, cleaning up alternative address\n");
       free_address (&n->alternative_address);
-      set_state (n, GNUNET_TRANSPORT_PS_CONNECTED);
+      set_state_and_timeout (n,
+                             GNUNET_TRANSPORT_PS_CONNECTED,
+                             n->timeout);
       break;
     }
     /* ATS asks us to switch a life connection, send */
-    set_alternative_address (n, blc_ctx->address, blc_ctx->session,
-        blc_ctx->bandwidth_in, blc_ctx->bandwidth_out);
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT,
-        GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
+    set_alternative_address (n,
+                            address,
+                             session,
+                             blc_ctx->bandwidth_in,
+                             blc_ctx->bandwidth_out);
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT,
+                           GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
     send_syn (&n->alternative_address);
     break;
   case GNUNET_TRANSPORT_PS_DISCONNECT:
     /* not going to switch addresses while disconnecting */
+    GNUNET_STATISTICS_update (GST_stats,
+                              "# ATS suggestion ignored (disconnecting)",
+                              1,
+                              GNUNET_NO);
     return;
   case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
     GNUNET_assert (0);
@@ -2791,9 +2758,10 @@ switch_address_bl_check_cont (void *cls,
     GNUNET_break (0);
     break;
   }
-
-  GNUNET_CONTAINER_DLL_remove (pending_bc_head, pending_bc_tail, blc_ctx);
-  GNUNET_HELLO_address_free (blc_ctx->address);
+ cleanup:
+  GNUNET_CONTAINER_DLL_remove (pending_bc_head,
+                               pending_bc_tail,
+                               blc_ctx);
   GNUNET_free (blc_ctx);
 }
 
@@ -2802,7 +2770,11 @@ switch_address_bl_check_cont (void *cls,
  * For the given peer, switch to this address.
  *
  * Before accepting this addresses and actively using it, a blacklist check
- * is performed. If this blacklist check fails the address will be destroyed.
+ * is performed.
+ *
+ * If any check fails or the suggestion can somehow not be followed, we
+ * MUST call #GST_ats_block_address() to tell ATS that the suggestion
+ * could not be satisfied and force ATS to do something else.
  *
  * @param address address of the other peer,
  * @param session session to use or NULL if transport should initiate a session
@@ -2817,27 +2789,24 @@ GST_neighbours_switch_to_address (const struct GNUNET_HELLO_Address *address,
                                  struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in,
                                  struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out)
 {
-  struct NeighbourMapEntry *n;
   struct GST_BlacklistCheck *blc;
   struct BlacklistCheckSwitchContext *blc_ctx;
 
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "ATS has decided on an address for peer %s\n",
-              GNUNET_i2s (&address->peer));
   GNUNET_assert (NULL != address->transport_name);
-  if (NULL == (n = lookup_neighbour (&address->peer)))
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "Peer %s is unknown, suggestion ignored\n",
-                GNUNET_i2s (&address->peer));
+  if (GNUNET_OK ==
+      try_run_fast_ats_update (address,
+                               session,
+                               bandwidth_in,
+                               bandwidth_out))
     return;
-  }
 
   /* Check if plugin is available */
   if (NULL == (GST_plugins_find (address->transport_name)))
   {
     /* we don't have the plugin for this address */
     GNUNET_break (0);
+    GST_ats_block_address (address,
+                           session);
     return;
   }
   if ((NULL == session) &&
@@ -2846,24 +2815,20 @@ GST_neighbours_switch_to_address (const struct GNUNET_HELLO_Address *address,
   {
     /* This is a inbound address and we do not have a session to use! */
     GNUNET_break (0);
+    GST_ats_block_address (address,
+                           session);
     return;
   }
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "ATS suggests %s address '%s' session %p for "
-             "peer `%s' in state %s/%s \n",
-             GNUNET_HELLO_address_check_option (address,
-                                                GNUNET_HELLO_ADDRESS_INFO_INBOUND) ? "inbound" : "outbound",
+             "ATS suggests address '%s' for peer `%s' at %u/%u speed\n",
              GST_plugins_a2s (address),
-             session,
              GNUNET_i2s (&address->peer),
-             GNUNET_TRANSPORT_ps2s (n->state),
-             print_ack_state (n->ack_state));
+              (unsigned int) ntohl (bandwidth_in.value__),
+              (unsigned int) ntohl (bandwidth_out.value__));
 
   /* Perform blacklist check */
   blc_ctx = GNUNET_new (struct BlacklistCheckSwitchContext);
-  blc_ctx->address = GNUNET_HELLO_address_copy (address);
-  blc_ctx->session = session;
   blc_ctx->bandwidth_in = bandwidth_in;
   blc_ctx->bandwidth_out = bandwidth_out;
   GNUNET_CONTAINER_DLL_insert (pending_bc_head,
@@ -2872,7 +2837,9 @@ GST_neighbours_switch_to_address (const struct GNUNET_HELLO_Address *address,
   if (NULL != (blc = GST_blacklist_test_allowed (&address->peer,
                                                  address->transport_name,
                                                  &switch_address_bl_check_cont,
-                                                 blc_ctx)))
+                                                 blc_ctx,
+                                                address,
+                                                session)))
   {
     blc_ctx->blc = blc;
   }
@@ -2894,30 +2861,15 @@ send_utilization_data (void *cls,
                        void *value)
 {
   struct NeighbourMapEntry *n = value;
-  struct GNUNET_ATS_Information atsi[4];
-  uint32_t bps_pl_in;
-  uint32_t bps_pl_out;
   uint32_t bps_in;
   uint32_t bps_out;
   struct GNUNET_TIME_Relative delta;
 
-  if (GNUNET_TRANSPORT_PS_CONNECTED != n->state)
+  if ( (GNUNET_YES != test_connected (n)) ||
+       (NULL == n->primary_address.address) )
     return GNUNET_OK;
   delta = GNUNET_TIME_absolute_get_difference (n->last_util_transmission,
                                                GNUNET_TIME_absolute_get ());
-
-  bps_pl_in = 0;
-
-  if ((0 != n->util_payload_bytes_recv) && (0 != delta.rel_value_us))
-    bps_pl_in =  (1000LL * 1000LL *  n->util_payload_bytes_recv) / (delta.rel_value_us);
-  bps_pl_out = 0;
-  if ((0 != n->util_payload_bytes_sent) && (0 != delta.rel_value_us))
-    bps_pl_out = (1000LL * 1000LL * n->util_payload_bytes_sent) / delta.rel_value_us;
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "`%s' payload: received %u Bytes/s, sent %u Bytes/s\n",
-              GNUNET_i2s (key),
-              bps_pl_in,
-              bps_pl_out);
   bps_in = 0;
   if ((0 != n->util_total_bytes_recv) && (0 != delta.rel_value_us))
     bps_in =  (1000LL * 1000LL *  n->util_total_bytes_recv) / (delta.rel_value_us);
@@ -2925,30 +2877,17 @@ send_utilization_data (void *cls,
   if ((0 != n->util_total_bytes_sent) && (0 != delta.rel_value_us))
     bps_out = (1000LL * 1000LL * n->util_total_bytes_sent) / delta.rel_value_us;
 
-
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "`%s' total: received %u Bytes/s, sent %u Bytes/s\n",
               GNUNET_i2s (key),
               bps_in,
               bps_out);
-  atsi[0].type = htonl (GNUNET_ATS_UTILIZATION_OUT);
-  atsi[0].value = htonl (bps_out);
-  atsi[1].type = htonl (GNUNET_ATS_UTILIZATION_IN);
-  atsi[1].value = htonl (bps_in);
-
-  atsi[2].type = htonl (GNUNET_ATS_UTILIZATION_PAYLOAD_OUT);
-  atsi[2].value = htonl (bps_pl_out);
-  atsi[3].type = htonl (GNUNET_ATS_UTILIZATION_PAYLOAD_IN);
-  atsi[3].value = htonl (bps_pl_in);
-
-  GST_ats_update_metrics (n->primary_address.address,
-                          n->primary_address.session,
-                          atsi, 4);
-  n->util_payload_bytes_recv = 0;
-  n->util_payload_bytes_sent = 0;
+  GST_ats_update_utilization (n->primary_address.address,
+                              bps_in,
+                              bps_out);
   n->util_total_bytes_recv = 0;
   n->util_total_bytes_sent = 0;
-  n->last_util_transmission = GNUNET_TIME_absolute_get();
+  n->last_util_transmission = GNUNET_TIME_absolute_get ();
   return GNUNET_OK;
 }
 
@@ -2964,19 +2903,26 @@ utilization_transmission (void *cls,
                           const struct GNUNET_SCHEDULER_TaskContext *tc)
 {
   util_transmission_tk = NULL;
-
-  if (0 < GNUNET_CONTAINER_multipeermap_size (neighbours))
-    GNUNET_CONTAINER_multipeermap_iterate (neighbours, send_utilization_data, NULL);
-
-  util_transmission_tk = GNUNET_SCHEDULER_add_delayed (UTIL_TRANSMISSION_INTERVAL,
-      utilization_transmission, NULL);
-
+  GNUNET_CONTAINER_multipeermap_iterate (neighbours,
+                                         &send_utilization_data,
+                                         NULL);
+  util_transmission_tk
+    = GNUNET_SCHEDULER_add_delayed (UTIL_TRANSMISSION_INTERVAL,
+                                    &utilization_transmission,
+                                    NULL);
 }
 
 
+/**
+ * Track information about data we received from the
+ * given address (used to notify ATS about our utilization
+ * of allocated resources).
+ *
+ * @param address the address we got data from
+ * @param message the message we received (really only the size is used)
+ */
 void
 GST_neighbours_notify_data_recv (const struct GNUNET_HELLO_Address *address,
-                                 struct Session *session,
                                  const struct GNUNET_MessageHeader *message)
 {
   struct NeighbourMapEntry *n;
@@ -2984,24 +2930,19 @@ GST_neighbours_notify_data_recv (const struct GNUNET_HELLO_Address *address,
   n = lookup_neighbour (&address->peer);
   if (NULL == n)
     return;
-  n->util_total_bytes_recv += ntohs(message->size);
-}
-
-
-void
-GST_neighbours_notify_payload_recv (const struct GNUNET_HELLO_Address *address,
-                                    struct Session *session,
-                                    const struct GNUNET_MessageHeader *message)
-{
-  struct NeighbourMapEntry *n;
-
-  n = lookup_neighbour (&address->peer);
-  if (NULL == n)
-    return;
-  n->util_payload_bytes_recv += ntohs(message->size);
+  n->util_total_bytes_recv += ntohs (message->size);
 }
 
 
+/**
+ * Track information about data we transmitted using the given @a
+ * address and @a session (used to notify ATS about our utilization of
+ * allocated resources).
+ *
+ * @param address the address we transmitted data to
+ * @param session session we used to transmit data
+ * @param message the message we sent (really only the size is used)
+ */
 void
 GST_neighbours_notify_data_sent (const struct GNUNET_HELLO_Address *address,
                                  struct Session *session,
@@ -3018,18 +2959,6 @@ GST_neighbours_notify_data_sent (const struct GNUNET_HELLO_Address *address,
 }
 
 
-void
-GST_neighbours_notify_payload_sent (const struct GNUNET_PeerIdentity *peer,
-                                    size_t size)
-{
-  struct NeighbourMapEntry *n;
-  n = lookup_neighbour (peer);
-  if (NULL == n)
-    return;
-  n->util_payload_bytes_sent += size;
-}
-
-
 /**
  * Master task run for every neighbour.  Performs all of the time-related
  * activities (keep alive, send next message, disconnect if idle, finish
@@ -3058,7 +2987,7 @@ master_task (void *cls,
   case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
     /* invalid state for master task, clean up */
     GNUNET_break (0);
-    free_neighbour (n, GNUNET_NO);
+    free_neighbour (n);
     return;
   case GNUNET_TRANSPORT_PS_INIT_ATS:
     if (0 == delay.rel_value_us)
@@ -3066,7 +2995,7 @@ master_task (void *cls,
       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                  "Connection to `%s' timed out waiting for ATS to provide address\n",
                  GNUNET_i2s (&n->id));
-      free_neighbour (n, GNUNET_NO);
+      free_neighbour (n);
       return;
     }
     break;
@@ -3078,8 +3007,9 @@ master_task (void *cls,
                  GNUNET_i2s (&n->id));
       /* Remove address and request and additional one */
       unset_primary_address (n);
-      set_state_and_timeout (n, GNUNET_TRANSPORT_PS_INIT_ATS,
-          GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
+      set_state_and_timeout (n,
+                             GNUNET_TRANSPORT_PS_INIT_ATS,
+                             GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
       return;
     }
     break;
@@ -3089,7 +3019,7 @@ master_task (void *cls,
       GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                  "Connection to `%s' timed out waiting ATS to provide address to use for SYN_ACK\n",
                  GNUNET_i2s (&n->id));
-      free_neighbour (n, GNUNET_NO);
+      free_neighbour (n);
       return;
     }
     break;
@@ -3138,15 +3068,12 @@ master_task (void *cls,
   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
     if (0 == delay.rel_value_us)
     {
-      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-                 "Connection to `%s' timed out, missing KEEPALIVE_RESPONSEs (after trying to SYN on alternative address)\n",
-                 GNUNET_i2s (&n->id));
-      GNUNET_STATISTICS_update (GST_stats,
-                                gettext_noop ("# Failed attempts to switch addresses (no response)"),
-                                1,
-                                GNUNET_NO);
-      disconnect_neighbour (n);
-      return;
+      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                  "Switch failed, cleaning up alternative address\n");
+      free_address (&n->alternative_address);
+      set_state_and_timeout (n,
+                             GNUNET_TRANSPORT_PS_CONNECTED,
+                             GNUNET_TIME_relative_to_absolute (SETUP_CONNECTION_TIMEOUT));
     }
     try_transmission_to_peer (n);
     send_keepalive (n);
@@ -3155,7 +3082,7 @@ master_task (void *cls,
     GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "Cleaning up connection to `%s' after sending DISCONNECT\n",
                GNUNET_i2s (&n->id));
-    free_neighbour (n, GNUNET_NO);
+    free_neighbour (n);
     return;
   case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
     /* how did we get here!? */
@@ -3168,6 +3095,7 @@ master_task (void *cls,
     GNUNET_break (0);
     break;
   }
+  delay = GNUNET_TIME_absolute_get_remaining (n->timeout);
   if ( (GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT == n->state) ||
        (GNUNET_TRANSPORT_PS_CONNECTED == n->state) )
   {
@@ -3195,15 +3123,19 @@ send_session_ack_message (struct NeighbourMapEntry *n)
 {
   struct GNUNET_MessageHeader msg;
 
-  GNUNET_log (GNUNET_ERROR_TYPE_INFO, "Sending ACK message to peer `%s'\n",
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "Sending ACK message to peer `%s'\n",
               GNUNET_i2s (&n->id));
 
   msg.size = htons (sizeof (struct GNUNET_MessageHeader));
   msg.type = htons (GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_ACK);
-  (void) send_with_session(n,
-                          (const char *) &msg, sizeof (struct GNUNET_MessageHeader),
-                          UINT32_MAX, GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_NO,
-                          NULL, NULL);
+  (void) send_with_session (n,
+                            &msg,
+                            sizeof (struct GNUNET_MessageHeader),
+                            UINT32_MAX,
+                            GNUNET_TIME_UNIT_FOREVER_REL,
+                            GNUNET_NO,
+                            NULL, NULL);
 }
 
 
@@ -3211,7 +3143,7 @@ send_session_ack_message (struct NeighbourMapEntry *n)
  * We received a 'SESSION_SYN_ACK' message from the other peer.
  * Consider switching to it.
  *
- * @param message possibly a 'struct SessionConnectMessage' (check format)
+ * @param message possibly a `struct SessionConnectMessage` (check format)
  * @param peer identity of the peer to switch the address for
  * @param address address of the other peer, NULL if other peer
  *                       connected to us
@@ -3227,10 +3159,6 @@ GST_neighbours_handle_session_syn_ack (const struct GNUNET_MessageHeader *messag
   struct GNUNET_TIME_Absolute ts;
   struct NeighbourMapEntry *n;
 
-  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              "Received SYN_ACK message from peer `%s'\n",
-              GNUNET_i2s (&address->peer));
-
   if (ntohs (message->size) != sizeof (struct TransportSynMessage))
   {
     GNUNET_break_op (0);
@@ -3250,18 +3178,23 @@ GST_neighbours_handle_session_syn_ack (const struct GNUNET_MessageHeader *messag
                               1, GNUNET_NO);
     return GNUNET_SYSERR;
   }
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Received SYN_ACK message from peer `%s' in state %s/%s\n",
+              GNUNET_i2s (&address->peer),
+              GNUNET_TRANSPORT_ps2s (n->state),
+              print_ack_state (n->ack_state));
   ts = GNUNET_TIME_absolute_ntoh (scm->timestamp);
   switch (n->state)
   {
   case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
     GNUNET_break (0);
-    free_neighbour (n, GNUNET_NO);
+    free_neighbour (n);
     return GNUNET_SYSERR;
   case GNUNET_TRANSPORT_PS_INIT_ATS:
     GNUNET_STATISTICS_update (GST_stats,
-                              gettext_noop
-                              ("# unexpected SYN_ACK messages (not ready)"),
-                              1, GNUNET_NO);
+                              gettext_noop ("# unexpected SYN_ACK messages (not ready)"),
+                              1,
+                              GNUNET_NO);
     break;
   case GNUNET_TRANSPORT_PS_SYN_SENT:
     if (ts.abs_value_us != n->primary_address.connect_timestamp.abs_value_us)
@@ -3270,30 +3203,22 @@ GST_neighbours_handle_session_syn_ack (const struct GNUNET_MessageHeader *messag
                   "SYN_ACK ignored as the timestamp does not match our SYN request\n");
       return GNUNET_OK;
     }
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_CONNECTED,
-        GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
-    GNUNET_STATISTICS_set (GST_stats,
-                          gettext_noop ("# peers connected"),
-                          ++neighbours_connected,
-                          GNUNET_NO);
-    neighbours_connect_notification (&n->id,
-                                     n->primary_address.bandwidth_in,
-                                     n->primary_address.bandwidth_out);
-    /* Tell ATS that the outbound session we created to send SYN was successful */
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_CONNECTED,
+                           GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
     set_primary_address (n,
                          n->primary_address.address,
                          n->primary_address.session,
                          n->primary_address.bandwidth_in,
-                         n->primary_address.bandwidth_out,
-                         GNUNET_YES);
+                         n->primary_address.bandwidth_out);
     send_session_ack_message (n);
     break;
   case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
   case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
     GNUNET_STATISTICS_update (GST_stats,
-                              gettext_noop
-                              ("# unexpected SYN_ACK messages (not ready)"),
-                              1, GNUNET_NO);
+                              gettext_noop ("# unexpected SYN_ACK messages (not ready)"),
+                              1,
+                              GNUNET_NO);
     break;
   case GNUNET_TRANSPORT_PS_CONNECTED:
     /* duplicate SYN_ACK, let's answer by duplicate ACK just in case */
@@ -3303,30 +3228,39 @@ GST_neighbours_handle_session_syn_ack (const struct GNUNET_MessageHeader *messag
     /* we didn't expect any SYN_ACK, as we are waiting for ATS
        to give us a new address... */
     GNUNET_STATISTICS_update (GST_stats,
-                              gettext_noop
-                              ("# unexpected SYN_ACK messages (waiting on ATS)"),
-                              1, GNUNET_NO);
+                              gettext_noop ("# unexpected SYN_ACK messages (waiting on ATS)"),
+                              1,
+                              GNUNET_NO);
     break;
   case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
     /* Reconnecting with new address address worked; go back to connected! */
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_CONNECTED,
-        GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_CONNECTED,
+                           GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
     send_session_ack_message (n);
     break;
   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
     /* new address worked; adopt it and go back to connected! */
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_CONNECTED,
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_CONNECTED,
                            GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
     GNUNET_break (GNUNET_NO == n->alternative_address.ats_active);
 
     /* Set primary addresses */
-    set_primary_address (n, n->alternative_address.address,
-        n->alternative_address.session, n->alternative_address.bandwidth_in,
-        n->alternative_address.bandwidth_out, GNUNET_YES);
-    GNUNET_STATISTICS_update (GST_stats, gettext_noop
-        ("# Successful attempts to switch addresses"), 1, GNUNET_NO);
+    set_primary_address (n,
+                         n->alternative_address.address,
+                         n->alternative_address.session,
+                         n->alternative_address.bandwidth_in,
+                         n->alternative_address.bandwidth_out);
+    GNUNET_STATISTICS_update (GST_stats,
+                              gettext_noop ("# Successful attempts to switch addresses"),
+                              1,
+                              GNUNET_NO);
 
-    free_address (&n->alternative_address);
+    GNUNET_HELLO_address_free (n->alternative_address.address);
+    memset (&n->alternative_address,
+            0,
+            sizeof (n->alternative_address));
     send_session_ack_message (n);
     break;
   case GNUNET_TRANSPORT_PS_DISCONNECT:
@@ -3389,8 +3323,12 @@ GST_neighbours_session_terminated (const struct GNUNET_PeerIdentity *peer,
     /* Free alternative address */
     if (session == n->alternative_address.session)
     {
-      if ( (GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT == n->state) )
-        set_state (n, GNUNET_TRANSPORT_PS_CONNECTED);
+      if (GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT == n->state)
+        set_state_and_timeout (n,
+                               GNUNET_TRANSPORT_PS_CONNECTED,
+                               n->timeout);
+      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                  "Session died, cleaning up alternative address\n");
       free_address (&n->alternative_address);
     }
     return GNUNET_NO; /* doesn't affect us further */
@@ -3402,11 +3340,11 @@ GST_neighbours_session_terminated (const struct GNUNET_PeerIdentity *peer,
   {
   case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
     GNUNET_break (0);
-    free_neighbour (n, GNUNET_NO);
+    free_neighbour (n);
     return GNUNET_YES;
   case GNUNET_TRANSPORT_PS_INIT_ATS:
     GNUNET_break (0);
-    free_neighbour (n, GNUNET_NO);
+    free_neighbour (n);
     return GNUNET_YES;
   case GNUNET_TRANSPORT_PS_SYN_SENT:
     /* The session used to send the SYN terminated:
@@ -3420,20 +3358,21 @@ GST_neighbours_session_terminated (const struct GNUNET_PeerIdentity *peer,
 
     /* Destroy the address since it cannot be used */
     unset_primary_address (n);
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_INIT_ATS,
-        GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_INIT_ATS,
+                           GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
     break;
   case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
   case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
     /* error on inbound session; free neighbour entirely */
-    free_address (&n->primary_address);
-    free_neighbour (n, GNUNET_NO);
+    free_neighbour (n);
     return GNUNET_YES;
   case GNUNET_TRANSPORT_PS_CONNECTED:
     /* Our primary connection died, try a fast reconnect */
     unset_primary_address (n);
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_RECONNECT_ATS,
-        GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_RECONNECT_ATS,
+                           GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
     break;
   case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
     /* we don't have an address, how can it go down? */
@@ -3448,36 +3387,42 @@ GST_neighbours_session_terminated (const struct GNUNET_PeerIdentity *peer,
                 GNUNET_i2s (peer));
     /* Destroy the address since it cannot be used */
     unset_primary_address (n);
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_RECONNECT_ATS,
-        GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_RECONNECT_ATS,
+                           GNUNET_TIME_relative_to_absolute (ATS_RESPONSE_TIMEOUT));
     break;
   case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
     /* primary went down while we were waiting for SYN_ACK on secondary;
        secondary as primary */
 
-    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-        "Connection `%s' %p to peer `%s' was terminated while switching, "
-        "switching to alternative address `%s' %p\n",
-        GST_plugins_a2s (n->primary_address.address),
-        n->primary_address.session,
-        GNUNET_i2s (peer),
-        GST_plugins_a2s (n->alternative_address.address),
-        n->alternative_address.session);
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Connection `%s' %p to peer `%s' was terminated while switching, "
+                "switching to alternative address `%s' %p\n",
+                GST_plugins_a2s (n->primary_address.address),
+                n->primary_address.session,
+                GNUNET_i2s (peer),
+                GST_plugins_a2s (n->alternative_address.address),
+                n->alternative_address.session);
 
     /* Destroy the inbound address since it cannot be used */
     free_address (&n->primary_address);
     n->primary_address = n->alternative_address;
-    memset (&n->alternative_address, 0, sizeof (struct NeighbourAddress));
-    set_state_and_timeout (n, GNUNET_TRANSPORT_PS_RECONNECT_SENT,
-        GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
+    GNUNET_assert (GNUNET_YES ==
+                   GST_ats_is_known (n->primary_address.address,
+                                     n->primary_address.session));
+    memset (&n->alternative_address,
+            0,
+            sizeof (struct NeighbourAddress));
+    set_state_and_timeout (n,
+                           GNUNET_TRANSPORT_PS_RECONNECT_SENT,
+                           GNUNET_TIME_relative_to_absolute (FAST_RECONNECT_TIMEOUT));
     break;
   case GNUNET_TRANSPORT_PS_DISCONNECT:
-    free_address (&n->primary_address);
+    unset_primary_address (n);
     break;
   case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
     /* neighbour was freed and plugins told to terminate session */
     return GNUNET_NO;
-    break;
   default:
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                 "Unhandled state `%s'\n",
@@ -3509,27 +3454,22 @@ GST_neighbours_handle_session_ack (const struct GNUNET_MessageHeader *message,
 {
   struct NeighbourMapEntry *n;
 
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "Received ACK message from peer `%s'\n",
-              GNUNET_i2s (&address->peer));
   if (ntohs (message->size) != sizeof (struct GNUNET_MessageHeader))
   {
     GNUNET_break_op (0);
     return GNUNET_SYSERR;
   }
   GNUNET_STATISTICS_update (GST_stats,
-                            gettext_noop
-                            ("# ACK messages received"),
-                            1, GNUNET_NO);
+                            gettext_noop ("# ACK messages received"),
+                            1,
+                            GNUNET_NO);
   if (NULL == (n = lookup_neighbour (&address->peer)))
   {
     GNUNET_break_op (0);
     return GNUNET_SYSERR;
   }
-
-  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
-              "Received %s for peer `%s' in state %s/%s\n",
-              "ACK",
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Received ACK for peer `%s' in state %s/%s\n",
               GNUNET_i2s (&address->peer),
               GNUNET_TRANSPORT_ps2s (n->state),
               print_ack_state (n->ack_state));
@@ -3555,24 +3495,11 @@ GST_neighbours_handle_session_ack (const struct GNUNET_MessageHeader *message,
                 print_ack_state (n->ack_state));
 
     GNUNET_STATISTICS_update (GST_stats,
-                              gettext_noop ("# unexpected ACK messages"), 1,
+                              gettext_noop ("# unexpected ACK messages"),
+                              1,
                               GNUNET_NO);
     return GNUNET_OK;
   }
-
-  /* We are connected */
-  if (GNUNET_NO == GST_neighbours_test_connected(&n->id))
-  {
-    /* Notify about connection */
-    neighbours_connect_notification (&n->id,
-                                     n->primary_address.bandwidth_in,
-                                     n->primary_address.bandwidth_out);
-    GNUNET_STATISTICS_set (GST_stats,
-                          gettext_noop ("# peers connected"),
-                          ++neighbours_connected,
-                          GNUNET_NO);
-  }
-
   if (GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT == n->state)
   {
     /* We tried to switch addresses while being connect. We explicitly wait
@@ -3580,17 +3507,13 @@ GST_neighbours_handle_session_ack (const struct GNUNET_MessageHeader *message,
      * so we do not want to set the address as in use! */
     return GNUNET_OK;
   }
+  set_state_and_timeout (n,
+                         GNUNET_TRANSPORT_PS_CONNECTED,
+                         GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
 
-  set_state_and_timeout (n, GNUNET_TRANSPORT_PS_CONNECTED,
-    GNUNET_TIME_relative_to_absolute (GNUNET_CONSTANTS_IDLE_CONNECTION_TIMEOUT));
-
-  /* Set primary address to used */
-  set_primary_address (n,
-                       n->primary_address.address,
-                       n->primary_address.session,
-                       n->primary_address.bandwidth_in,
-                       n->primary_address.bandwidth_out,
-                       GNUNET_YES);
+  /* Reset backoff for primary address */
+  GST_ats_block_reset (n->primary_address.address,
+                       n->primary_address.session);
   return GNUNET_OK;
 }
 
@@ -3645,6 +3568,12 @@ GST_neighbours_set_incoming_quota (const struct GNUNET_PeerIdentity *neighbour,
 }
 
 
+/**
+ * Task to asynchronously run #free_neighbour().
+ *
+ * @param cls the `struct NeighbourMapEntry` to free
+ * @param tc unused
+ */
 static void
 delayed_disconnect (void *cls,
                     const struct GNUNET_SCHEDULER_TaskContext* tc)
@@ -3655,7 +3584,7 @@ delayed_disconnect (void *cls,
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
               "Disconnecting by request from peer %s\n",
               GNUNET_i2s (&n->id));
-  free_neighbour (n, GNUNET_NO);
+  free_neighbour (n);
 }
 
 
@@ -3691,16 +3620,21 @@ GST_neighbours_handle_disconnect_message (const struct GNUNET_PeerIdentity *peer
                             1, GNUNET_NO);
   sdm = (const struct SessionDisconnectMessage *) msg;
   if (NULL == (n = lookup_neighbour (peer)))
-    return;                     /* gone already */
+  {
+    /* gone already */
+    return;
+  }
   if (GNUNET_TIME_absolute_ntoh (sdm->timestamp).abs_value_us <= n->connect_ack_timestamp.abs_value_us)
   {
     GNUNET_STATISTICS_update (GST_stats,
-                              gettext_noop
-                              ("# disconnect messages ignored (timestamp)"), 1,
+                              gettext_noop ("# disconnect messages ignored (timestamp)"),
+                              1,
                               GNUNET_NO);
     return;
   }
-  if (0 != memcmp (peer, &sdm->public_key, sizeof (struct GNUNET_PeerIdentity)))
+  if (0 != memcmp (peer,
+                   &sdm->public_key,
+                   sizeof (struct GNUNET_PeerIdentity)))
   {
     GNUNET_break_op (0);
     return;
@@ -3710,21 +3644,20 @@ GST_neighbours_handle_disconnect_message (const struct GNUNET_PeerIdentity *peer
       sizeof (struct GNUNET_CRYPTO_EddsaPublicKey) +
       sizeof (struct GNUNET_TIME_AbsoluteNBO))
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                "%s message from peer `%s' has invalid size \n",
-                "DISCONNECT",
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "DISCONNECT message from peer `%s' has invalid size\n",
                 GNUNET_i2s (peer));
     GNUNET_break_op (0);
     return;
   }
   if (GNUNET_OK !=
-      GNUNET_CRYPTO_eddsa_verify
-      (GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_DISCONNECT, &sdm->purpose,
-       &sdm->signature, &sdm->public_key))
+      GNUNET_CRYPTO_eddsa_verify (GNUNET_MESSAGE_TYPE_TRANSPORT_SESSION_DISCONNECT,
+                                  &sdm->purpose,
+                                  &sdm->signature,
+                                  &sdm->public_key))
   {
-    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
-                "%s message from peer `%s' cannot be verified \n",
-                "DISCONNECT",
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "DISCONNECT message from peer `%s' cannot be verified \n",
                 GNUNET_i2s (peer));
     GNUNET_break_op (0);
     return;
@@ -3768,7 +3701,6 @@ neighbours_iterate (void *cls,
   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_in;
   struct GNUNET_BANDWIDTH_Value32NBO bandwidth_out;
 
-
   if (NULL != n->primary_address.address)
   {
     bandwidth_in = n->primary_address.bandwidth_in;
@@ -3804,7 +3736,9 @@ GST_neighbours_iterate (GST_NeighbourIterator cb, void *cb_cls)
     return; /* can happen during shutdown */
   ic.cb = cb;
   ic.cb_cls = cb_cls;
-  GNUNET_CONTAINER_multipeermap_iterate (neighbours, &neighbours_iterate, &ic);
+  GNUNET_CONTAINER_multipeermap_iterate (neighbours,
+                                         &neighbours_iterate,
+                                         &ic);
 }
 
 
@@ -3822,8 +3756,8 @@ GST_neighbours_force_disconnect (const struct GNUNET_PeerIdentity *target)
     return;  /* not active */
   if (GNUNET_YES == test_connected (n))
     GNUNET_STATISTICS_update (GST_stats,
-                             gettext_noop
-                             ("# disconnected from peer upon explicit request"), 1,
+                             gettext_noop ("# disconnected from peer upon explicit request"),
+                              1,
                              GNUNET_NO);
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
               "Forced disconnect from peer %s\n",
@@ -3832,47 +3766,6 @@ GST_neighbours_force_disconnect (const struct GNUNET_PeerIdentity *target)
 }
 
 
-/**
- * Obtain current latency information for the given neighbour.
- *
- * @param peer to get the latency for
- * @return observed latency of the address, FOREVER if the
- *         the connection is not up
- */
-struct GNUNET_TIME_Relative
-GST_neighbour_get_latency (const struct GNUNET_PeerIdentity *peer)
-{
-  struct NeighbourMapEntry *n;
-
-  n = lookup_neighbour (peer);
-  if (NULL == n)
-    return GNUNET_TIME_UNIT_FOREVER_REL;
-  switch (n->state)
-  {
-  case GNUNET_TRANSPORT_PS_CONNECTED:
-  case GNUNET_TRANSPORT_PS_SWITCH_SYN_SENT:
-  case GNUNET_TRANSPORT_PS_RECONNECT_SENT:
-  case GNUNET_TRANSPORT_PS_RECONNECT_ATS:
-    return n->latency;
-  case GNUNET_TRANSPORT_PS_NOT_CONNECTED:
-  case GNUNET_TRANSPORT_PS_INIT_ATS:
-  case GNUNET_TRANSPORT_PS_SYN_RECV_ATS:
-  case GNUNET_TRANSPORT_PS_SYN_RECV_ACK:
-  case GNUNET_TRANSPORT_PS_SYN_SENT:
-  case GNUNET_TRANSPORT_PS_DISCONNECT:
-  case GNUNET_TRANSPORT_PS_DISCONNECT_FINISHED:
-    return GNUNET_TIME_UNIT_FOREVER_REL;
-  default:
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                "Unhandled state `%s'\n",
-                GNUNET_TRANSPORT_ps2s (n->state));
-    GNUNET_break (0);
-    break;
-  }
-  return GNUNET_TIME_UNIT_FOREVER_REL;
-}
-
-
 /**
  * Obtain current address information for the given neighbour.
  *
@@ -3899,10 +3792,11 @@ GST_neighbour_get_current_address (const struct GNUNET_PeerIdentity *peer)
 void
 GST_neighbours_start (unsigned int max_fds)
 {
-  neighbours = GNUNET_CONTAINER_multipeermap_create (NEIGHBOUR_TABLE_SIZE, GNUNET_NO);
-  registered_quota_notifications = GNUNET_CONTAINER_multipeermap_create (NEIGHBOUR_TABLE_SIZE, GNUNET_NO);
+  neighbours = GNUNET_CONTAINER_multipeermap_create (NEIGHBOUR_TABLE_SIZE,
+                                                     GNUNET_NO);
   util_transmission_tk = GNUNET_SCHEDULER_add_delayed (UTIL_TRANSMISSION_INTERVAL,
-      utilization_transmission, NULL);
+                                                       &utilization_transmission,
+                                                       NULL);
 }
 
 
@@ -3922,9 +3816,9 @@ disconnect_all_neighbours (void *cls,
   struct NeighbourMapEntry *n = value;
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-             "Disconnecting peer `%4s', %s\n",
-              GNUNET_i2s (&n->id), "SHUTDOWN_TASK");
-  free_neighbour (n, GNUNET_NO);
+             "Disconnecting peer `%4s' during shutdown\n",
+              GNUNET_i2s (&n->id));
+  free_neighbour (n);
   return GNUNET_OK;
 }
 
@@ -3949,7 +3843,7 @@ GST_neighbours_stop ()
                                          &disconnect_all_neighbours,
                                          NULL);
   GNUNET_CONTAINER_multipeermap_destroy (neighbours);
-
+  neighbours = NULL;
   next = pending_bc_head;
   for (cur = next; NULL != cur; cur = next)
   {
@@ -3963,17 +3857,8 @@ GST_neighbours_stop ()
       GST_blacklist_test_cancel (cur->blc);
       cur->blc = NULL;
     }
-    if (NULL != cur->address)
-      GNUNET_HELLO_address_free (cur->address);
     GNUNET_free (cur);
   }
-
-  GNUNET_CONTAINER_multipeermap_iterate (registered_quota_notifications,
-                                         &free_notification_cb, NULL);
-  GNUNET_CONTAINER_multipeermap_destroy (registered_quota_notifications);
-  registered_quota_notifications = NULL;
-
-  neighbours = NULL;
 }