session: cleanup part 2

Move app worker logic to app_worker.c

Change-Id: Ic5e5735b2884f006c064d023f491aa6888114810
Signed-off-by: Florin Coras <fcoras@cisco.com>

8 files changed, 1228 insertions, 1191 deletions

diff --git a/src/vnet/CMakeLists.txt b/src/vnet/CMakeLists.txt
index e14f0877bd5..72da325a08f 100644
--- a/src/vnet/CMakeLists.txt
+++ b/src/vnet/CMakeLists.txt
@@ -1038,6 +1038,7 @@ list(APPEND VNET_SOURCES
   session/session_node.c
   session/transport.c
   session/application.c
+  session/application_worker.c
   session/session_cli.c
   session/application_interface.c
   session/application_namespace.c
diff --git a/src/vnet/session/application.c b/src/vnet/session/application.c
index 268816561a7..3380d0bca4a 100644
--- a/src/vnet/session/application.c
+++ b/src/vnet/session/application.c
@@ -497,104 +497,8 @@ application_listener_select_worker (session_t * ls, u8 is_local)
   return application_get_worker (app, wrk_index);
 }
 
-app_worker_t *
-app_worker_alloc (application_t * app)
-{
-  app_worker_t *app_wrk;
-  pool_get (app_main.workers, app_wrk);
-  clib_memset (app_wrk, 0, sizeof (*app_wrk));
-  app_wrk->wrk_index = app_wrk - app_main.workers;
-  app_wrk->app_index = app->app_index;
-  app_wrk->wrk_map_index = ~0;
-  app_wrk->connects_seg_manager = APP_INVALID_SEGMENT_MANAGER_INDEX;
-  app_wrk->first_segment_manager = APP_INVALID_SEGMENT_MANAGER_INDEX;
-  app_wrk->local_segment_manager = APP_INVALID_SEGMENT_MANAGER_INDEX;
-  APP_DBG ("New app %v worker %u", app_get_name (app), app_wrk->wrk_index);
-  return app_wrk;
-}
-
-app_worker_t *
-app_worker_get (u32 wrk_index)
-{
-  return pool_elt_at_index (app_main.workers, wrk_index);
-}
-
-app_worker_t *
-app_worker_get_if_valid (u32 wrk_index)
-{
-  if (pool_is_free_index (app_main.workers, wrk_index))
-    return 0;
-  return pool_elt_at_index (app_main.workers, wrk_index);
-}
-
-void
-app_worker_free (app_worker_t * app_wrk)
-{
-  application_t *app = application_get (app_wrk->app_index);
-  vnet_unbind_args_t _a, *a = &_a;
-  u64 handle, *handles = 0;
-  segment_manager_t *sm;
-  u32 sm_index;
-  int i;
-
-  /*
-   *  Listener cleanup
-   */
-
-  /* *INDENT-OFF* */
-  hash_foreach (handle, sm_index, app_wrk->listeners_table,
-  ({
-    vec_add1 (handles, handle);
-    sm = segment_manager_get (sm_index);
-    sm->app_wrk_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
-  }));
-  /* *INDENT-ON* */
-
-  for (i = 0; i < vec_len (handles); i++)
-    {
-      a->app_index = app->app_index;
-      a->wrk_map_index = app_wrk->wrk_map_index;
-      a->handle = handles[i];
-      /* seg manager is removed when unbind completes */
-      vnet_unbind (a);
-    }
-
-  /*
-   * Connects segment manager cleanup
-   */
-
-  if (app_wrk->connects_seg_manager != APP_INVALID_SEGMENT_MANAGER_INDEX)
-    {
-      sm = segment_manager_get (app_wrk->connects_seg_manager);
-      sm->app_wrk_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
-      segment_manager_init_del (sm);
-    }
-
-  /* If first segment manager is used by a listener */
-  if (app_wrk->first_segment_manager != APP_INVALID_SEGMENT_MANAGER_INDEX
-      && app_wrk->first_segment_manager != app_wrk->connects_seg_manager)
-    {
-      sm = segment_manager_get (app_wrk->first_segment_manager);
-      sm->first_is_protected = 0;
-      sm->app_wrk_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
-      /* .. and has no fifos, e.g. it might be used for redirected sessions,
-       * remove it */
-      if (!segment_manager_has_fifos (sm))
-	segment_manager_del (sm);
-    }
-
-  /*
-   * Local sessions
-   */
-  app_worker_local_sessions_free (app_wrk);
-
-  pool_put (app_main.workers, app_wrk);
-  if (CLIB_DEBUG)
-    clib_memset (app_wrk, 0xfe, sizeof (*app_wrk));
-}
-
 int
-app_worker_alloc_and_init (application_t * app, app_worker_t ** wrk)
+application_alloc_worker_and_init (application_t * app, app_worker_t ** wrk)
 {
   app_worker_map_t *wrk_map;
   app_worker_t *app_wrk;
@@ -641,160 +545,6 @@ app_worker_alloc_and_init (application_t * app, app_worker_t ** wrk)
   return 0;
 }
 
-application_t *
-app_worker_get_app (u32 wrk_index)
-{
-  app_worker_t *app_wrk;
-  app_wrk = app_worker_get_if_valid (wrk_index);
-  if (!app_wrk)
-    return 0;
-  return application_get_if_valid (app_wrk->app_index);
-}
-
-static segment_manager_t *
-app_worker_alloc_segment_manager (app_worker_t * app_wrk)
-{
-  segment_manager_t *sm = 0;
-
-  /* If the first segment manager is not in use, don't allocate a new one */
-  if (app_wrk->first_segment_manager != APP_INVALID_SEGMENT_MANAGER_INDEX
-      && app_wrk->first_segment_manager_in_use == 0)
-    {
-      sm = segment_manager_get (app_wrk->first_segment_manager);
-      app_wrk->first_segment_manager_in_use = 1;
-      return sm;
-    }
-
-  sm = segment_manager_new ();
-  sm->app_wrk_index = app_wrk->wrk_index;
-
-  return sm;
-}
-
-int
-app_worker_start_listen (app_worker_t * app_wrk, session_t * ls)
-{
-  segment_manager_t *sm;
-
-  /* Allocate segment manager. All sessions derived out of a listen session
-   * have fifos allocated by the same segment manager. */
-  if (!(sm = app_worker_alloc_segment_manager (app_wrk)))
-    return -1;
-
-  /* Add to app's listener table. Useful to find all child listeners
-   * when app goes down, although, just for unbinding this is not needed */
-  hash_set (app_wrk->listeners_table, listen_session_get_handle (ls),
-	    segment_manager_index (sm));
-
-  if (!ls->rx_fifo
-      && session_transport_service_type (ls) == TRANSPORT_SERVICE_CL)
-    {
-      if (session_alloc_fifos (sm, ls))
-	return -1;
-    }
-  return 0;
-}
-
-int
-app_worker_stop_listen (app_worker_t * app_wrk, session_handle_t handle)
-{
-  segment_manager_t *sm;
-  uword *sm_indexp;
-
-  sm_indexp = hash_get (app_wrk->listeners_table, handle);
-  if (PREDICT_FALSE (!sm_indexp))
-    {
-      clib_warning ("listener handle was removed %llu!", handle);
-      return -1;
-    }
-
-  sm = segment_manager_get (*sm_indexp);
-  if (app_wrk->first_segment_manager == *sm_indexp)
-    {
-      /* Delete sessions but don't remove segment manager */
-      app_wrk->first_segment_manager_in_use = 0;
-      segment_manager_del_sessions (sm);
-    }
-  else
-    {
-      segment_manager_init_del (sm);
-    }
-  hash_unset (app_wrk->listeners_table, handle);
-
-  return 0;
-}
-
-int
-app_worker_own_session (app_worker_t * app_wrk, session_t * s)
-{
-  segment_manager_t *sm;
-  svm_fifo_t *rxf, *txf;
-
-  if (s->session_state == SESSION_STATE_LISTENING)
-    {
-      app_worker_t *old_wrk = app_worker_get (s->app_wrk_index);
-      u64 lsh = listen_session_get_handle (s);
-      app_listener_t *app_listener;
-      application_t *app;
-
-      if (!old_wrk)
-	return -1;
-
-      hash_unset (old_wrk->listeners_table, lsh);
-      if (!(sm = app_worker_alloc_segment_manager (app_wrk)))
-	return -1;
-
-      hash_set (app_wrk->listeners_table, lsh, segment_manager_index (sm));
-      s->app_wrk_index = app_wrk->wrk_index;
-
-      app = application_get (old_wrk->app_index);
-      if (!app)
-	return -1;
-
-      app_listener = app_listener_get (app, s->listener_db_index);
-      app_listener->workers = clib_bitmap_set (app_listener->workers,
-					       app_wrk->wrk_map_index, 1);
-      app_listener->workers = clib_bitmap_set (app_listener->workers,
-					       old_wrk->wrk_map_index, 0);
-      return 0;
-    }
-
-  s->app_wrk_index = app_wrk->wrk_index;
-
-  rxf = s->rx_fifo;
-  txf = s->tx_fifo;
-
-  if (!rxf || !txf)
-    return 0;
-
-  s->rx_fifo = 0;
-  s->tx_fifo = 0;
-
-  sm = app_worker_get_or_alloc_connect_segment_manager (app_wrk);
-  if (session_alloc_fifos (sm, s))
-    return -1;
-
-  if (!svm_fifo_is_empty (rxf))
-    {
-      clib_memcpy_fast (s->rx_fifo->data, rxf->data, rxf->nitems);
-      s->rx_fifo->head = rxf->head;
-      s->rx_fifo->tail = rxf->tail;
-      s->rx_fifo->cursize = rxf->cursize;
-    }
-
-  if (!svm_fifo_is_empty (txf))
-    {
-      clib_memcpy_fast (s->tx_fifo->data, txf->data, txf->nitems);
-      s->tx_fifo->head = txf->head;
-      s->tx_fifo->tail = txf->tail;
-      s->tx_fifo->cursize = txf->cursize;
-    }
-
-  segment_manager_dealloc_fifos (rxf->segment_index, rxf, txf);
-
-  return 0;
-}
-
 /**
  * Start listening local transport endpoint for requested transport.
  *
@@ -877,6 +627,39 @@ err:
   return -1;
 }
 
+int
+application_change_listener_owner (session_t * s, app_worker_t * app_wrk)
+{
+  app_worker_t *old_wrk = app_worker_get (s->app_wrk_index);
+  app_listener_t *app_listener;
+  application_t *app;
+
+  if (!old_wrk)
+    return -1;
+
+  hash_unset (old_wrk->listeners_table, listen_session_get_handle (s));
+  if (session_transport_service_type (s) == TRANSPORT_SERVICE_CL
+      && s->rx_fifo)
+    segment_manager_dealloc_fifos (s->rx_fifo->segment_index, s->rx_fifo,
+				   s->tx_fifo);
+
+  if (app_worker_start_listen (app_wrk, s))
+    return -1;
+
+  s->app_wrk_index = app_wrk->wrk_index;
+
+  app = application_get (old_wrk->app_index);
+  if (!app)
+    return -1;
+
+  app_listener = app_listener_get (app, s->listener_db_index);
+  app_listener->workers = clib_bitmap_set (app_listener->workers,
+					   app_wrk->wrk_map_index, 1);
+  app_listener->workers = clib_bitmap_set (app_listener->workers,
+					   old_wrk->wrk_map_index, 0);
+  return 0;
+}
+
 /**
  * Stop listening on session associated to handle
  *
@@ -923,61 +706,6 @@ application_stop_listen (u32 app_index, u32 app_wrk_index,
   return 0;
 }
 
-int
-app_worker_open_session (app_worker_t * app, session_endpoint_t * sep,
-			 u32 api_context)
-{
-  int rv;
-
-  /* Make sure we have a segment manager for connects */
-  app_worker_alloc_connects_segment_manager (app);
-
-  if ((rv = session_open (app->wrk_index, sep, api_context)))
-    return rv;
-
-  return 0;
-}
-
-int
-app_worker_alloc_connects_segment_manager (app_worker_t * app_wrk)
-{
-  segment_manager_t *sm;
-
-  if (app_wrk->connects_seg_manager == APP_INVALID_SEGMENT_MANAGER_INDEX)
-    {
-      sm = app_worker_alloc_segment_manager (app_wrk);
-      if (sm == 0)
-	return -1;
-      app_wrk->connects_seg_manager = segment_manager_index (sm);
-    }
-  return 0;
-}
-
-segment_manager_t *
-app_worker_get_connect_segment_manager (app_worker_t * app)
-{
-  ASSERT (app->connects_seg_manager != (u32) ~ 0);
-  return segment_manager_get (app->connects_seg_manager);
-}
-
-segment_manager_t *
-app_worker_get_or_alloc_connect_segment_manager (app_worker_t * app_wrk)
-{
-  if (app_wrk->connects_seg_manager == (u32) ~ 0)
-    app_worker_alloc_connects_segment_manager (app_wrk);
-  return segment_manager_get (app_wrk->connects_seg_manager);
-}
-
-segment_manager_t *
-app_worker_get_listen_segment_manager (app_worker_t * app,
-				       session_t * listener)
-{
-  uword *smp;
-  smp = hash_get (app->listeners_table, listen_session_get_handle (listener));
-  ASSERT (smp != 0);
-  return segment_manager_get (*smp);
-}
-
 clib_error_t *
 vnet_app_worker_add_del (vnet_app_worker_add_del_args_t * a)
 {
@@ -995,7 +723,7 @@ vnet_app_worker_add_del (vnet_app_worker_add_del_args_t * a)
 
   if (a->is_add)
     {
-      if ((rv = app_worker_alloc_and_init (app, &app_wrk)))
+      if ((rv = application_alloc_worker_and_init (app, &app_wrk)))
 	return clib_error_return_code (0, rv, 0, "app wrk init: %d", rv);
 
       /* Map worker api index to the app */
@@ -1030,25 +758,6 @@ vnet_app_worker_add_del (vnet_app_worker_add_del_args_t * a)
   return 0;
 }
 
-segment_manager_t *
-application_get_local_segment_manager (app_worker_t * app)
-{
-  return segment_manager_get (app->local_segment_manager);
-}
-
-segment_manager_t *
-application_get_local_segment_manager_w_session (app_worker_t * app,
-						 local_session_t * ls)
-{
-  session_t *listener;
-  if (application_local_session_listener_has_transport (ls))
-    {
-      listener = listen_session_get (ls->listener_index);
-      return app_worker_get_listen_segment_manager (app, listener);
-    }
-  return segment_manager_get (app->local_segment_manager);
-}
-
 int
 application_is_proxy (application_t * app)
 {
@@ -1085,78 +794,6 @@ application_use_mq_for_ctrl (application_t * app)
   return app->flags & APP_OPTIONS_FLAGS_USE_MQ_FOR_CTRL_MSGS;
 }
 
-/**
- * Send an API message to the external app, to map new segment
- */
-int
-app_worker_add_segment_notify (u32 app_wrk_index, u64 segment_handle)
-{
-  app_worker_t *app_wrk = app_worker_get (app_wrk_index);
-  application_t *app = application_get (app_wrk->app_index);
-  return app->cb_fns.add_segment_callback (app_wrk->api_client_index,
-					   segment_handle);
-}
-
-u32
-application_n_listeners (app_worker_t * app)
-{
-  return hash_elts (app->listeners_table);
-}
-
-session_t *
-app_worker_first_listener (app_worker_t * app, u8 fib_proto,
-			   u8 transport_proto)
-{
-  session_t *listener;
-  u64 handle;
-  u32 sm_index;
-  u8 sst;
-
-  sst = session_type_from_proto_and_ip (transport_proto,
-					fib_proto == FIB_PROTOCOL_IP4);
-
-  /* *INDENT-OFF* */
-   hash_foreach (handle, sm_index, app->listeners_table, ({
-     listener = listen_session_get_from_handle (handle);
-     if (listener->session_type == sst
-	 && listener->enqueue_epoch != SESSION_PROXY_LISTENER_INDEX)
-       return listener;
-   }));
-  /* *INDENT-ON* */
-
-  return 0;
-}
-
-u8
-app_worker_application_is_builtin (app_worker_t * app_wrk)
-{
-  return app_wrk->app_is_builtin;
-}
-
-session_t *
-application_proxy_listener (app_worker_t * app, u8 fib_proto,
-			    u8 transport_proto)
-{
-  session_t *listener;
-  u64 handle;
-  u32 sm_index;
-  u8 sst;
-
-  sst = session_type_from_proto_and_ip (transport_proto,
-					fib_proto == FIB_PROTOCOL_IP4);
-
-  /* *INDENT-OFF* */
-   hash_foreach (handle, sm_index, app->listeners_table, ({
-     listener = listen_session_get_from_handle (handle);
-     if (listener->session_type == sst
-	 && listener->enqueue_epoch == SESSION_PROXY_LISTENER_INDEX)
-       return listener;
-   }));
-  /* *INDENT-ON* */
-
-  return 0;
-}
-
 static clib_error_t *
 application_start_stop_proxy_fib_proto (application_t * app, u8 fib_proto,
 					u8 transport_proto, u8 is_start)
@@ -1188,7 +825,7 @@ application_start_stop_proxy_fib_proto (application_t * app, u8 fib_proto,
     }
   else
     {
-      s = application_proxy_listener (app_wrk, fib_proto, transport_proto);
+      s = app_worker_proxy_listener (app_wrk, fib_proto, transport_proto);
       ASSERT (s);
     }
 
@@ -1302,193 +939,6 @@ application_get_segment_manager_properties (u32 app_index)
   return &app->sm_properties;
 }
 
-static inline int
-app_enqueue_evt (svm_msg_q_t * mq, svm_msg_q_msg_t * msg, u8 lock)
-{
-  if (PREDICT_FALSE (svm_msg_q_is_full (mq)))
-    {
-      clib_warning ("evt q full");
-      svm_msg_q_free_msg (mq, msg);
-      if (lock)
-	svm_msg_q_unlock (mq);
-      return -1;
-    }
-
-  if (lock)
-    {
-      svm_msg_q_add_and_unlock (mq, msg);
-      return 0;
-    }
-
-  /* Even when not locking the ring, we must wait for queue mutex */
-  if (svm_msg_q_add (mq, msg, SVM_Q_WAIT))
-    {
-      clib_warning ("msg q add returned");
-      return -1;
-    }
-  return 0;
-}
-
-static inline int
-app_send_io_evt_rx (app_worker_t * app_wrk, session_t * s, u8 lock)
-{
-  session_event_t *evt;
-  svm_msg_q_msg_t msg;
-  svm_msg_q_t *mq;
-
-  if (PREDICT_FALSE (s->session_state != SESSION_STATE_READY
-		     && s->session_state != SESSION_STATE_LISTENING))
-    {
-      /* Session is closed so app will never clean up. Flush rx fifo */
-      if (s->session_state == SESSION_STATE_CLOSED)
-	svm_fifo_dequeue_drop_all (s->rx_fifo);
-      return 0;
-    }
-
-  if (app_worker_application_is_builtin (app_wrk))
-    {
-      application_t *app = application_get (app_wrk->app_index);
-      return app->cb_fns.builtin_app_rx_callback (s);
-    }
-
-  if (svm_fifo_has_event (s->rx_fifo) || svm_fifo_is_empty (s->rx_fifo))
-    return 0;
-
-  mq = app_wrk->event_queue;
-  if (lock)
-    svm_msg_q_lock (mq);
-
-  if (PREDICT_FALSE (svm_msg_q_ring_is_full (mq, SESSION_MQ_IO_EVT_RING)))
-    {
-      clib_warning ("evt q rings full");
-      if (lock)
-	svm_msg_q_unlock (mq);
-      return -1;
-    }
-
-  msg = svm_msg_q_alloc_msg_w_ring (mq, SESSION_MQ_IO_EVT_RING);
-  ASSERT (!svm_msg_q_msg_is_invalid (&msg));
-
-  evt = (session_event_t *) svm_msg_q_msg_data (mq, &msg);
-  evt->fifo = s->rx_fifo;
-  evt->event_type = FIFO_EVENT_APP_RX;
-
-  (void) svm_fifo_set_event (s->rx_fifo);
-
-  if (app_enqueue_evt (mq, &msg, lock))
-    return -1;
-  return 0;
-}
-
-static inline int
-app_send_io_evt_tx (app_worker_t * app_wrk, session_t * s, u8 lock)
-{
-  svm_msg_q_t *mq;
-  session_event_t *evt;
-  svm_msg_q_msg_t msg;
-
-  if (app_worker_application_is_builtin (app_wrk))
-    return 0;
-
-  mq = app_wrk->event_queue;
-  if (lock)
-    svm_msg_q_lock (mq);
-
-  if (PREDICT_FALSE (svm_msg_q_ring_is_full (mq, SESSION_MQ_IO_EVT_RING)))
-    {
-      clib_warning ("evt q rings full");
-      if (lock)
-	svm_msg_q_unlock (mq);
-      return -1;
-    }
-
-  msg = svm_msg_q_alloc_msg_w_ring (mq, SESSION_MQ_IO_EVT_RING);
-  ASSERT (!svm_msg_q_msg_is_invalid (&msg));
-
-  evt = (session_event_t *) svm_msg_q_msg_data (mq, &msg);
-  evt->event_type = FIFO_EVENT_APP_TX;
-  evt->fifo = s->tx_fifo;
-
-  return app_enqueue_evt (mq, &msg, lock);
-}
-
-/* *INDENT-OFF* */
-typedef int (app_send_evt_handler_fn) (app_worker_t *app,
-				       session_t *s,
-				       u8 lock);
-static app_send_evt_handler_fn * const app_send_evt_handler_fns[3] = {
-    app_send_io_evt_rx,
-    0,
-    app_send_io_evt_tx,
-};
-/* *INDENT-ON* */
-
-/**
- * Send event to application
- *
- * Logic from queue perspective is non-blocking. If there's
- * not enough space to enqueue a message, we return.
- */
-int
-app_worker_send_event (app_worker_t * app, session_t * s, u8 evt_type)
-{
-  ASSERT (app && evt_type <= FIFO_EVENT_APP_TX);
-  return app_send_evt_handler_fns[evt_type] (app, s, 0 /* lock */ );
-}
-
-/**
- * Send event to application
- *
- * Logic from queue perspective is blocking. However, if queue is full,
- * we return.
- */
-int
-app_worker_lock_and_send_event (app_worker_t * app, session_t * s,
-				u8 evt_type)
-{
-  return app_send_evt_handler_fns[evt_type] (app, s, 1 /* lock */ );
-}
-
-local_session_t *
-application_local_session_alloc (app_worker_t * app_wrk)
-{
-  local_session_t *s;
-  pool_get (app_wrk->local_sessions, s);
-  clib_memset (s, 0, sizeof (*s));
-  s->app_wrk_index = app_wrk->wrk_index;
-  s->session_index = s - app_wrk->local_sessions;
-  s->session_type = session_type_from_proto_and_ip (TRANSPORT_PROTO_NONE, 0);
-  return s;
-}
-
-void
-application_local_session_free (app_worker_t * app, local_session_t * s)
-{
-  pool_put (app->local_sessions, s);
-  if (CLIB_DEBUG)
-    clib_memset (s, 0xfc, sizeof (*s));
-}
-
-local_session_t *
-application_get_local_session (app_worker_t * app_wrk, u32 session_index)
-{
-  if (pool_is_free_index (app_wrk->local_sessions, session_index))
-    return 0;
-  return pool_elt_at_index (app_wrk->local_sessions, session_index);
-}
-
-local_session_t *
-application_get_local_session_from_handle (session_handle_t handle)
-{
-  app_worker_t *server_wrk;
-  u32 session_index, server_wrk_index;
-  local_session_parse_handle (handle, &server_wrk_index, &session_index);
-  server_wrk = app_worker_get_if_valid (server_wrk_index);
-  if (!server_wrk)
-    return 0;
-  return application_get_local_session (server_wrk, session_index);
-}
-
 local_session_t *
 application_local_listen_session_alloc (application_t * app)
 {
@@ -1591,7 +1041,7 @@ application_stop_local_listen (u32 app_index, u32 wrk_map_index,
   table_index = application_local_session_table (server);
 
   /* We have both local and global table binds. Figure from global what
-   * the sep we should be cleaning up is.
+   * sep we should be cleaning up.
    */
   if (!session_handle_is_local (lh))
     {
@@ -1632,7 +1082,7 @@ application_stop_local_listen (u32 app_index, u32 wrk_map_index,
   /* *INDENT-OFF* */
   pool_foreach (ls, server_wrk->local_sessions, ({
     if (ls->listener_index == ll->session_index)
-      application_local_session_disconnect (server_wrk->app_index, ls);
+      app_worker_local_session_disconnect (server_wrk->app_index, ls);
   }));
   /* *INDENT-ON* */
 
@@ -1648,356 +1098,6 @@ application_stop_local_listen (u32 app_index, u32 wrk_map_index,
   return 0;
 }
 
-static void
-application_local_session_fix_eventds (svm_msg_q_t * sq, svm_msg_q_t * cq)
-{
-  int fd;
-
-  /*
-   * segment manager initializes only the producer eventds, since vpp is
-   * typically the producer. But for local sessions, we also pass to the
-   * apps the mqs they listen on for events from peer apps, so they are also
-   * consumer fds.
-   */
-  fd = svm_msg_q_get_producer_eventfd (sq);
-  svm_msg_q_set_consumer_eventfd (sq, fd);
-  fd = svm_msg_q_get_producer_eventfd (cq);
-  svm_msg_q_set_consumer_eventfd (cq, fd);
-}
-
-int
-application_local_session_connect (app_worker_t * client_wrk,
-				   app_worker_t * server_wrk,
-				   local_session_t * ll, u32 opaque)
-{
-  u32 seg_size, evt_q_sz, evt_q_elts, margin = 16 << 10;
-  u32 round_rx_fifo_sz, round_tx_fifo_sz, sm_index;
-  segment_manager_properties_t *props, *cprops;
-  int rv, has_transport, seg_index;
-  svm_fifo_segment_private_t *seg;
-  application_t *server, *client;
-  segment_manager_t *sm;
-  local_session_t *ls;
-  svm_msg_q_t *sq, *cq;
-  u64 segment_handle;
-
-  ls = application_local_session_alloc (server_wrk);
-  server = application_get (server_wrk->app_index);
-  client = application_get (client_wrk->app_index);
-
-  props = application_segment_manager_properties (server);
-  cprops = application_segment_manager_properties (client);
-  evt_q_elts = props->evt_q_size + cprops->evt_q_size;
-  evt_q_sz = segment_manager_evt_q_expected_size (evt_q_elts);
-  round_rx_fifo_sz = 1 << max_log2 (props->rx_fifo_size);
-  round_tx_fifo_sz = 1 << max_log2 (props->tx_fifo_size);
-  seg_size = round_rx_fifo_sz + round_tx_fifo_sz + evt_q_sz + margin;
-
-  has_transport = session_has_transport ((session_t *) ll);
-  if (!has_transport)
-    {
-      /* Local sessions don't have backing transport */
-      ls->port = ll->port;
-      sm = application_get_local_segment_manager (server_wrk);
-    }
-  else
-    {
-      session_t *sl = (session_t *) ll;
-      transport_connection_t *tc;
-      tc = listen_session_get_transport (sl);
-      ls->port = tc->lcl_port;
-      sm = app_worker_get_listen_segment_manager (server_wrk, sl);
-    }
-
-  seg_index = segment_manager_add_segment (sm, seg_size);
-  if (seg_index < 0)
-    {
-      clib_warning ("failed to add new cut-through segment");
-      return seg_index;
-    }
-  seg = segment_manager_get_segment_w_lock (sm, seg_index);
-  sq = segment_manager_alloc_queue (seg, props);
-  cq = segment_manager_alloc_queue (seg, cprops);
-
-  if (props->use_mq_eventfd)
-    application_local_session_fix_eventds (sq, cq);
-
-  ls->server_evt_q = pointer_to_uword (sq);
-  ls->client_evt_q = pointer_to_uword (cq);
-  rv = segment_manager_try_alloc_fifos (seg, props->rx_fifo_size,
-					props->tx_fifo_size,
-					&ls->rx_fifo, &ls->tx_fifo);
-  if (rv)
-    {
-      clib_warning ("failed to add fifos in cut-through segment");
-      segment_manager_segment_reader_unlock (sm);
-      goto failed;
-    }
-  sm_index = segment_manager_index (sm);
-  ls->rx_fifo->ct_session_index = ls->session_index;
-  ls->tx_fifo->ct_session_index = ls->session_index;
-  ls->rx_fifo->segment_manager = sm_index;
-  ls->tx_fifo->segment_manager = sm_index;
-  ls->rx_fifo->segment_index = seg_index;
-  ls->tx_fifo->segment_index = seg_index;
-  ls->svm_segment_index = seg_index;
-  ls->listener_index = ll->session_index;
-  ls->client_wrk_index = client_wrk->wrk_index;
-  ls->client_opaque = opaque;
-  ls->listener_session_type = ll->session_type;
-  ls->session_state = SESSION_STATE_READY;
-
-  segment_handle = segment_manager_segment_handle (sm, seg);
-  if ((rv = server->cb_fns.add_segment_callback (server_wrk->api_client_index,
-						 segment_handle)))
-    {
-      clib_warning ("failed to notify server of new segment");
-      segment_manager_segment_reader_unlock (sm);
-      goto failed;
-    }
-  segment_manager_segment_reader_unlock (sm);
-  if ((rv = server->cb_fns.session_accept_callback ((session_t *) ls)))
-    {
-      clib_warning ("failed to send accept cut-through notify to server");
-      goto failed;
-    }
-  if (server->flags & APP_OPTIONS_FLAGS_IS_BUILTIN)
-    application_local_session_connect_notify (ls);
-
-  return 0;
-
-failed:
-  if (!has_transport)
-    segment_manager_del_segment (sm, seg);
-  return rv;
-}
-
-static u64
-application_client_local_connect_key (local_session_t * ls)
-{
-  return (((u64) ls->app_wrk_index) << 32 | (u64) ls->session_index);
-}
-
-static void
-application_client_local_connect_key_parse (u64 key, u32 * app_wrk_index,
-					    u32 * session_index)
-{
-  *app_wrk_index = key >> 32;
-  *session_index = key & 0xFFFFFFFF;
-}
-
-int
-application_local_session_connect_notify (local_session_t * ls)
-{
-  svm_fifo_segment_private_t *seg;
-  app_worker_t *client_wrk, *server_wrk;
-  segment_manager_t *sm;
-  application_t *client;
-  int rv, is_fail = 0;
-  u64 segment_handle;
-  u64 client_key;
-
-  client_wrk = app_worker_get (ls->client_wrk_index);
-  server_wrk = app_worker_get (ls->app_wrk_index);
-  client = application_get (client_wrk->app_index);
-
-  sm = application_get_local_segment_manager_w_session (server_wrk, ls);
-  seg = segment_manager_get_segment_w_lock (sm, ls->svm_segment_index);
-  segment_handle = segment_manager_segment_handle (sm, seg);
-  if ((rv = client->cb_fns.add_segment_callback (client_wrk->api_client_index,
-						 segment_handle)))
-    {
-      clib_warning ("failed to notify client %u of new segment",
-		    ls->client_wrk_index);
-      segment_manager_segment_reader_unlock (sm);
-      application_local_session_disconnect (ls->client_wrk_index, ls);
-      is_fail = 1;
-    }
-  else
-    {
-      segment_manager_segment_reader_unlock (sm);
-    }
-
-  client->cb_fns.session_connected_callback (client_wrk->wrk_index,
-					     ls->client_opaque,
-					     (session_t *) ls, is_fail);
-
-  client_key = application_client_local_connect_key (ls);
-  hash_set (client_wrk->local_connects, client_key, client_key);
-  return 0;
-}
-
-int
-application_local_session_cleanup (app_worker_t * client_wrk,
-				   app_worker_t * server_wrk,
-				   local_session_t * ls)
-{
-  svm_fifo_segment_private_t *seg;
-  session_t *listener;
-  segment_manager_t *sm;
-  u64 client_key;
-  u8 has_transport;
-
-  /* Retrieve listener transport type as it is the one that decides where
-   * the fifos are allocated */
-  has_transport = application_local_session_listener_has_transport (ls);
-  if (!has_transport)
-    sm = application_get_local_segment_manager_w_session (server_wrk, ls);
-  else
-    {
-      listener = listen_session_get (ls->listener_index);
-      sm = app_worker_get_listen_segment_manager (server_wrk, listener);
-    }
-
-  seg = segment_manager_get_segment (sm, ls->svm_segment_index);
-  if (client_wrk)
-    {
-      client_key = application_client_local_connect_key (ls);
-      hash_unset (client_wrk->local_connects, client_key);
-    }
-
-  if (!has_transport)
-    {
-      application_t *server = application_get (server_wrk->app_index);
-      u64 segment_handle = segment_manager_segment_handle (sm, seg);
-      server->cb_fns.del_segment_callback (server_wrk->api_client_index,
-					   segment_handle);
-      if (client_wrk)
-	{
-	  application_t *client = application_get (client_wrk->app_index);
-	  client->cb_fns.del_segment_callback (client_wrk->api_client_index,
-					       segment_handle);
-	}
-      segment_manager_del_segment (sm, seg);
-    }
-
-  application_local_session_free (server_wrk, ls);
-
-  return 0;
-}
-
-int
-application_local_session_disconnect (u32 app_index, local_session_t * ls)
-{
-  app_worker_t *client_wrk, *server_wrk;
-  u8 is_server = 0, is_client = 0;
-  application_t *app;
-
-  app = application_get_if_valid (app_index);
-  if (!app)
-    return 0;
-
-  client_wrk = app_worker_get_if_valid (ls->client_wrk_index);
-  server_wrk = app_worker_get (ls->app_wrk_index);
-
-  if (server_wrk->app_index == app_index)
-    is_server = 1;
-  else if (client_wrk && client_wrk->app_index == app_index)
-    is_client = 1;
-
-  if (!is_server && !is_client)
-    {
-      clib_warning ("app %u is neither client nor server for session 0x%lx",
-		    app_index, application_local_session_handle (ls));
-      return VNET_API_ERROR_INVALID_VALUE;
-    }
-
-  if (ls->session_state == SESSION_STATE_CLOSED)
-    return application_local_session_cleanup (client_wrk, server_wrk, ls);
-
-  if (app_index == ls->client_wrk_index)
-    {
-      mq_send_local_session_disconnected_cb (ls->app_wrk_index, ls);
-    }
-  else
-    {
-      if (!client_wrk)
-	{
-	  return application_local_session_cleanup (client_wrk, server_wrk,
-						    ls);
-	}
-      else if (ls->session_state < SESSION_STATE_READY)
-	{
-	  application_t *client = application_get (client_wrk->app_index);
-	  client->cb_fns.session_connected_callback (client_wrk->wrk_index,
-						     ls->client_opaque,
-						     (session_t *) ls,
-						     1 /* is_fail */ );
-	  ls->session_state = SESSION_STATE_CLOSED;
-	  return application_local_session_cleanup (client_wrk, server_wrk,
-						    ls);
-	}
-      else
-	{
-	  mq_send_local_session_disconnected_cb (client_wrk->wrk_index, ls);
-	}
-    }
-
-  ls->session_state = SESSION_STATE_CLOSED;
-
-  return 0;
-}
-
-int
-application_local_session_disconnect_w_index (u32 app_wrk_index, u32 ls_index)
-{
-  app_worker_t *app_wrk;
-  local_session_t *ls;
-  app_wrk = app_worker_get (app_wrk_index);
-  ls = application_get_local_session (app_wrk, ls_index);
-  return application_local_session_disconnect (app_wrk_index, ls);
-}
-
-void
-app_worker_local_sessions_free (app_worker_t * app_wrk)
-{
-  u32 index, server_wrk_index, session_index;
-  u64 handle, *handles = 0;
-  app_worker_t *server_wrk;
-  segment_manager_t *sm;
-  local_session_t *ls;
-  int i;
-
-  /*
-   * Local sessions
-   */
-  if (app_wrk->local_sessions)
-    {
-      /* *INDENT-OFF* */
-      pool_foreach (ls, app_wrk->local_sessions, ({
-	application_local_session_disconnect (app_wrk->wrk_index, ls);
-      }));
-      /* *INDENT-ON* */
-    }
-
-  /*
-   * Local connects
-   */
-  vec_reset_length (handles);
-  /* *INDENT-OFF* */
-  hash_foreach (handle, index, app_wrk->local_connects, ({
-    vec_add1 (handles, handle);
-  }));
-  /* *INDENT-ON* */
-
-  for (i = 0; i < vec_len (handles); i++)
-    {
-      application_client_local_connect_key_parse (handles[i],
-						  &server_wrk_index,
-						  &session_index);
-      server_wrk = app_worker_get_if_valid (server_wrk_index);
-      if (server_wrk)
-	{
-	  ls = application_get_local_session (server_wrk, session_index);
-	  application_local_session_disconnect (app_wrk->wrk_index, ls);
-	}
-    }
-
-  sm = segment_manager_get (app_wrk->local_segment_manager);
-  sm->app_wrk_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
-  segment_manager_del (sm);
-}
-
 clib_error_t *
 vnet_app_add_tls_cert (vnet_app_add_tls_cert_args_t * a)
 {
@@ -2022,45 +1122,6 @@ vnet_app_add_tls_key (vnet_app_add_tls_key_args_t * a)
   return 0;
 }
 
-u8 *
-format_app_worker_listener (u8 * s, va_list * args)
-{
-  app_worker_t *app_wrk = va_arg (*args, app_worker_t *);
-  u64 handle = va_arg (*args, u64);
-  u32 sm_index = va_arg (*args, u32);
-  int verbose = va_arg (*args, int);
-  session_t *listener;
-  const u8 *app_name;
-  u8 *str;
-
-  if (!app_wrk)
-    {
-      if (verbose)
-	s = format (s, "%-40s%-25s%=10s%-15s%-15s%-10s", "Connection", "App",
-		    "Wrk", "API Client", "ListenerID", "SegManager");
-      else
-	s = format (s, "%-40s%-25s%=10s", "Connection", "App", "Wrk");
-
-      return s;
-    }
-
-  app_name = application_name_from_index (app_wrk->app_index);
-  listener = listen_session_get_from_handle (handle);
-  str = format (0, "%U", format_stream_session, listener, verbose);
-
-  if (verbose)
-    {
-      char buf[32];
-      sprintf (buf, "%u(%u)", app_wrk->wrk_map_index, app_wrk->wrk_index);
-      s = format (s, "%-40s%-25s%=10s%-15u%-15u%-10u", str, app_name,
-		  buf, app_wrk->api_client_index, handle, sm_index);
-    }
-  else
-    s = format (s, "%-40s%-25s%=10u", str, app_name, app_wrk->wrk_map_index);
-
-  return s;
-}
-
 static void
 application_format_listeners (application_t * app, int verbose)
 {
@@ -2091,69 +1152,6 @@ application_format_listeners (application_t * app, int verbose)
 }
 
 static void
-app_worker_format_connects (app_worker_t * app_wrk, int verbose)
-{
-  svm_fifo_segment_private_t *fifo_segment;
-  vlib_main_t *vm = vlib_get_main ();
-  segment_manager_t *sm;
-  const u8 *app_name;
-  u8 *s = 0;
-
-  /* Header */
-  if (!app_wrk)
-    {
-      if (verbose)
-	vlib_cli_output (vm, "%-40s%-20s%-15s%-10s", "Connection", "App",
-			 "API Client", "SegManager");
-      else
-	vlib_cli_output (vm, "%-40s%-20s", "Connection", "App");
-      return;
-    }
-
-  if (app_wrk->connects_seg_manager == (u32) ~ 0)
-    return;
-
-  app_name = application_name_from_index (app_wrk->app_index);
-
-  /* Across all fifo segments */
-  sm = segment_manager_get (app_wrk->connects_seg_manager);
-
-  /* *INDENT-OFF* */
-  segment_manager_foreach_segment_w_lock (fifo_segment, sm, ({
-    svm_fifo_t *fifo;
-    u8 *str;
-
-    fifo = svm_fifo_segment_get_fifo_list (fifo_segment);
-    while (fifo)
-      {
-        u32 session_index, thread_index;
-        session_t *session;
-
-        session_index = fifo->master_session_index;
-        thread_index = fifo->master_thread_index;
-
-        session = session_get (session_index, thread_index);
-        str = format (0, "%U", format_stream_session, session, verbose);
-
-        if (verbose)
-          s = format (s, "%-40s%-20s%-15u%-10u", str, app_name,
-                      app_wrk->api_client_index, app_wrk->connects_seg_manager);
-        else
-          s = format (s, "%-40s%-20s", str, app_name);
-
-        vlib_cli_output (vm, "%v", s);
-        vec_reset_length (s);
-        vec_free (str);
-
-        fifo = fifo->next;
-      }
-    vec_free (s);
-  }));
-  /* *INDENT-ON* */
-
-}
-
-static void
 application_format_connects (application_t * app, int verbose)
 {
   app_worker_map_t *wrk_map;
@@ -2174,40 +1172,6 @@ application_format_connects (application_t * app, int verbose)
 }
 
 static void
-app_worker_format_local_sessions (app_worker_t * app_wrk, int verbose)
-{
-  vlib_main_t *vm = vlib_get_main ();
-  local_session_t *ls;
-  transport_proto_t tp;
-  u8 *conn = 0;
-
-  /* Header */
-  if (app_wrk == 0)
-    {
-      vlib_cli_output (vm, "%-40s%-15s%-20s", "Connection", "ServerApp",
-		       "ClientApp");
-      return;
-    }
-
-  if (!pool_elts (app_wrk->local_sessions)
-      && !pool_elts (app_wrk->local_connects))
-    return;
-
-  /* *INDENT-OFF* */
-  pool_foreach (ls, app_wrk->local_sessions, ({
-    tp = session_type_transport_proto(ls->listener_session_type);
-    conn = format (0, "[L][%U] *:%u", format_transport_proto_short, tp,
-                   ls->port);
-    vlib_cli_output (vm, "%-40v%-15u%-20u", conn, ls->app_wrk_index,
-                     ls->client_wrk_index);
-    vec_reset_length (conn);
-  }));
-  /* *INDENT-ON* */
-
-  vec_free (conn);
-}
-
-static void
 application_format_local_sessions (application_t * app, int verbose)
 {
   vlib_main_t *vm = vlib_get_main ();
@@ -2249,43 +1213,6 @@ application_format_local_sessions (application_t * app, int verbose)
 }
 
 static void
-app_worker_format_local_connects (app_worker_t * app, int verbose)
-{
-  vlib_main_t *vm = vlib_get_main ();
-  u32 app_wrk_index, session_index;
-  app_worker_t *server_wrk;
-  local_session_t *ls;
-  u64 client_key;
-  u64 value;
-
-  /* Header */
-  if (app == 0)
-    {
-      if (verbose)
-	vlib_cli_output (vm, "%-40s%-15s%-20s%-10s", "Connection", "App",
-			 "Peer App", "SegManager");
-      else
-	vlib_cli_output (vm, "%-40s%-15s%-20s", "Connection", "App",
-			 "Peer App");
-      return;
-    }
-
-  if (!app->local_connects)
-    return;
-
-  /* *INDENT-OFF* */
-  hash_foreach (client_key, value, app->local_connects, ({
-    application_client_local_connect_key_parse (client_key, &app_wrk_index,
-                                                &session_index);
-    server_wrk = app_worker_get (app_wrk_index);
-    ls = application_get_local_session (server_wrk, session_index);
-    vlib_cli_output (vm, "%-40s%-15s%-20s", "TODO", ls->app_wrk_index,
-                     ls->client_wrk_index);
-  }));
-  /* *INDENT-ON* */
-}
-
-static void
 application_format_local_connects (application_t * app, int verbose)
 {
   app_worker_map_t *wrk_map;
@@ -2306,19 +1233,6 @@ application_format_local_connects (application_t * app, int verbose)
 }
 
 u8 *
-format_application_worker (u8 * s, va_list * args)
-{
-  app_worker_t *app_wrk = va_arg (*args, app_worker_t *);
-  u32 indent = 1;
-
-  s = format (s, "%U wrk-index %u app-index %u map-index %u "
-	      "api-client-index %d\n", format_white_space, indent,
-	      app_wrk->wrk_index, app_wrk->app_index, app_wrk->wrk_map_index,
-	      app_wrk->api_client_index);
-  return s;
-}
-
-u8 *
 format_application (u8 * s, va_list * args)
 {
   application_t *app = va_arg (*args, application_t *);
@@ -2355,7 +1269,7 @@ format_application (u8 * s, va_list * args)
   /* *INDENT-OFF* */
   pool_foreach (wrk_map, app->worker_maps, ({
       app_wrk = app_worker_get (wrk_map->wrk_index);
-      s = format (s, "%U", format_application_worker, app_wrk);
+      s = format (s, "%U", format_app_worker, app_wrk);
   }));
   /* *INDENT-ON* */
 
diff --git a/src/vnet/session/application.h b/src/vnet/session/application.h
index 0f8dbe3909b..54f998996e9 100644
--- a/src/vnet/session/application.h
+++ b/src/vnet/session/application.h
@@ -175,11 +175,6 @@ typedef struct app_main_
   application_t *app_pool;
 
   /**
-   * Pool of workers associated to apps
-   */
-  app_worker_t *workers;
-
-  /**
    * Hash table of apps by api client index
    */
   uword *app_by_api_client_index;
@@ -220,37 +215,6 @@ typedef struct _vnet_app_worker_add_del_args
 #define APP_NS_INVALID_INDEX ((u32)~0)
 #define APP_INVALID_SEGMENT_MANAGER_INDEX ((u32) ~0)
 
-app_worker_t *app_worker_alloc (application_t * app);
-int app_worker_alloc_and_init (application_t * app, app_worker_t ** wrk);
-app_worker_t *app_worker_get (u32 wrk_index);
-app_worker_t *app_worker_get_if_valid (u32 wrk_index);
-application_t *app_worker_get_app (u32 wrk_index);
-int app_worker_own_session (app_worker_t * app_wrk, session_t * s);
-void app_worker_free (app_worker_t * app_wrk);
-int app_worker_open_session (app_worker_t * app, session_endpoint_t * tep,
-			     u32 api_context);
-segment_manager_t *app_worker_get_listen_segment_manager (app_worker_t *,
-							  session_t *);
-segment_manager_t *app_worker_get_connect_segment_manager (app_worker_t *);
-segment_manager_t
-  * app_worker_get_or_alloc_connect_segment_manager (app_worker_t *);
-int app_worker_alloc_connects_segment_manager (app_worker_t * app);
-int app_worker_add_segment_notify (u32 app_or_wrk, u64 segment_handle);
-u32 app_worker_n_listeners (app_worker_t * app);
-session_t *app_worker_first_listener (app_worker_t * app,
-				      u8 fib_proto, u8 transport_proto);
-u8 app_worker_application_is_builtin (app_worker_t * app_wrk);
-int app_worker_send_event (app_worker_t * app, session_t * s, u8 evt);
-int app_worker_lock_and_send_event (app_worker_t * app, session_t * s,
-				    u8 evt_type);
-clib_error_t *vnet_app_worker_add_del (vnet_app_worker_add_del_args_t * a);
-
-int application_start_listen (application_t * app,
-			      session_endpoint_cfg_t * tep,
-			      session_handle_t * handle);
-int application_stop_listen (u32 app_index, u32 app_or_wrk,
-			     session_handle_t handle);
-
 application_t *application_alloc (void);
 int application_alloc_and_init (app_init_args_t * args);
 void application_free (application_t * app);
@@ -263,7 +227,12 @@ app_worker_t *application_get_worker (application_t * app, u32 wrk_index);
 app_worker_t *application_get_default_worker (application_t * app);
 app_worker_t *application_listener_select_worker (session_t * ls,
 						  u8 is_local);
-
+int application_start_listen (application_t * app,
+			      session_endpoint_cfg_t * tep,
+			      session_handle_t * handle);
+int application_stop_listen (u32 app_index, u32 app_or_wrk,
+			     session_handle_t handle);
+int application_change_listener_owner (session_t * s, app_worker_t * app_wrk);
 int application_is_proxy (application_t * app);
 int application_is_builtin (application_t * app);
 int application_is_builtin_proxy (application_t * app);
@@ -283,16 +252,52 @@ segment_manager_properties_t
   * application_segment_manager_properties (application_t * app);
 
 /*
+ * App worker
+ */
+
+app_worker_t *app_worker_alloc (application_t * app);
+int application_alloc_worker_and_init (application_t * app,
+				       app_worker_t ** wrk);
+app_worker_t *app_worker_get (u32 wrk_index);
+app_worker_t *app_worker_get_if_valid (u32 wrk_index);
+application_t *app_worker_get_app (u32 wrk_index);
+int app_worker_own_session (app_worker_t * app_wrk, session_t * s);
+void app_worker_free (app_worker_t * app_wrk);
+int app_worker_open_session (app_worker_t * app, session_endpoint_t * tep,
+			     u32 api_context);
+int app_worker_start_listen (app_worker_t * app_wrk, session_t * ls);
+int app_worker_stop_listen (app_worker_t * app_wrk, session_handle_t handle);
+segment_manager_t *app_worker_get_listen_segment_manager (app_worker_t *,
+							  session_t *);
+segment_manager_t *app_worker_get_connect_segment_manager (app_worker_t *);
+segment_manager_t
+  * app_worker_get_or_alloc_connect_segment_manager (app_worker_t *);
+int app_worker_alloc_connects_segment_manager (app_worker_t * app);
+int app_worker_add_segment_notify (u32 app_or_wrk, u64 segment_handle);
+u32 app_worker_n_listeners (app_worker_t * app);
+session_t *app_worker_first_listener (app_worker_t * app,
+				      u8 fib_proto, u8 transport_proto);
+u8 app_worker_application_is_builtin (app_worker_t * app_wrk);
+int app_worker_send_event (app_worker_t * app, session_t * s, u8 evt);
+int app_worker_lock_and_send_event (app_worker_t * app, session_t * s,
+				    u8 evt_type);
+session_t *app_worker_proxy_listener (app_worker_t * app, u8 fib_proto,
+				      u8 transport_proto);
+u8 *format_app_worker (u8 * s, va_list * args);
+u8 *format_app_worker_listener (u8 * s, va_list * args);
+void app_worker_format_connects (app_worker_t * app_wrk, int verbose);
+clib_error_t *vnet_app_worker_add_del (vnet_app_worker_add_del_args_t * a);
+
+/*
  * Local session
  */
 
-local_session_t *application_local_session_alloc (app_worker_t * app);
-void application_local_session_free (app_worker_t * app,
-				     local_session_t * ls);
-local_session_t *application_get_local_session (app_worker_t * app,
-						u32 session_index);
-local_session_t *application_get_local_session_from_handle (session_handle_t
-							    handle);
+local_session_t *app_worker_local_session_alloc (app_worker_t * app);
+void app_worker_local_session_free (app_worker_t * app, local_session_t * ls);
+local_session_t *app_worker_get_local_session (app_worker_t * app,
+					       u32 session_index);
+local_session_t *app_worker_get_local_session_from_handle (session_handle_t
+							   handle);
 local_session_t
   * application_get_local_listen_session_from_handle (session_handle_t lh);
 int application_start_local_listen (application_t * server,
@@ -300,15 +305,16 @@ int application_start_local_listen (application_t * server,
 				    session_handle_t * handle);
 int application_stop_local_listen (u32 app_index, u32 app_or_wrk,
 				   session_handle_t lh);
-int application_local_session_connect (app_worker_t * client,
-				       app_worker_t * server,
-				       local_session_t * ls, u32 opaque);
-int application_local_session_connect_notify (local_session_t * ls);
-int application_local_session_disconnect (u32 app_or_wrk,
-					  local_session_t * ls);
-int application_local_session_disconnect_w_index (u32 app_or_wrk,
-						  u32 ls_index);
-void app_worker_local_sessions_free (app_worker_t * app);
+int app_worker_local_session_connect (app_worker_t * client,
+				      app_worker_t * server,
+				      local_session_t * ls, u32 opaque);
+int app_worker_local_session_connect_notify (local_session_t * ls);
+int app_worker_local_session_disconnect (u32 app_or_wrk,
+					 local_session_t * ls);
+int app_worker_local_session_disconnect_w_index (u32 app_or_wrk,
+						 u32 ls_index);
+void app_worker_format_local_sessions (app_worker_t * app_wrk, int verbose);
+void app_worker_format_local_connects (app_worker_t * app, int verbose);
 
 always_inline u32
 local_session_id (local_session_t * ls)
diff --git a/src/vnet/session/application_interface.c b/src/vnet/session/application_interface.c
index 0245f58d3b1..c00c4ded1c7 100644
--- a/src/vnet/session/application_interface.c
+++ b/src/vnet/session/application_interface.c
@@ -329,9 +329,9 @@ application_connect (vnet_connect_args_t * a)
 	  listener = (session_t *) ll;
 	  server_wrk = application_listener_select_worker (listener,
 							   1 /* is_local */ );
-	  return application_local_session_connect (client_wrk,
-						    server_wrk, ll,
-						    a->api_context);
+	  return app_worker_local_session_connect (client_wrk,
+						   server_wrk, ll,
+						   a->api_context);
 	}
     }
 
@@ -355,8 +355,8 @@ global_scope:
       server_wrk = application_listener_select_worker (listener,
 						       0 /* is_local */ );
       ll = (local_session_t *) listener;
-      return application_local_session_connect (client_wrk, server_wrk, ll,
-						a->api_context);
+      return app_worker_local_session_connect (client_wrk, server_wrk, ll,
+					       a->api_context);
     }
 
   /*
@@ -545,7 +545,7 @@ vnet_application_attach (vnet_app_attach_args_t * a)
     return clib_error_return_code (0, rv, 0, "app init: %d", rv);
 
   app = application_get (a->app_index);
-  if ((rv = app_worker_alloc_and_init (app, &app_wrk)))
+  if ((rv = application_alloc_worker_and_init (app, &app_wrk)))
     return clib_error_return_code (0, rv, 0, "app default wrk init: %d", rv);
 
   a->app_evt_q = app_wrk->event_queue;
@@ -649,10 +649,10 @@ vnet_disconnect_session (vnet_disconnect_args_t * a)
       /* Disconnect reply came to worker 1 not main thread */
       app_interface_check_thread_and_barrier (vnet_disconnect_session, a);
 
-      if (!(ls = application_get_local_session_from_handle (a->handle)))
+      if (!(ls = app_worker_get_local_session_from_handle (a->handle)))
 	return 0;
 
-      return application_local_session_disconnect (a->app_index, ls);
+      return app_worker_local_session_disconnect (a->app_index, ls);
     }
   else
     {
diff --git a/src/vnet/session/application_worker.c b/src/vnet/session/application_worker.c
new file mode 100644
index 00000000000..89ee6057172
--- /dev/null
+++ b/src/vnet/session/application_worker.c
@@ -0,0 +1,1116 @@
+/*
+ * Copyright (c) 2019 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vnet/session/application.h>
+#include <vnet/session/application_interface.h>
+
+/**
+ * Pool of workers associated to apps
+ */
+static app_worker_t *app_workers;
+
+static inline u64
+application_client_local_connect_key (local_session_t * ls)
+{
+  return (((u64) ls->app_wrk_index) << 32 | (u64) ls->session_index);
+}
+
+static inline void
+application_client_local_connect_key_parse (u64 key, u32 * app_wrk_index,
+					    u32 * session_index)
+{
+  *app_wrk_index = key >> 32;
+  *session_index = key & 0xFFFFFFFF;
+}
+
+local_session_t *
+app_worker_local_session_alloc (app_worker_t * app_wrk)
+{
+  local_session_t *s;
+  pool_get (app_wrk->local_sessions, s);
+  clib_memset (s, 0, sizeof (*s));
+  s->app_wrk_index = app_wrk->wrk_index;
+  s->session_index = s - app_wrk->local_sessions;
+  s->session_type = session_type_from_proto_and_ip (TRANSPORT_PROTO_NONE, 0);
+  return s;
+}
+
+void
+app_worker_local_session_free (app_worker_t * app_wrk, local_session_t * s)
+{
+  pool_put (app_wrk->local_sessions, s);
+  if (CLIB_DEBUG)
+    clib_memset (s, 0xfc, sizeof (*s));
+}
+
+local_session_t *
+app_worker_get_local_session (app_worker_t * app_wrk, u32 session_index)
+{
+  if (pool_is_free_index (app_wrk->local_sessions, session_index))
+    return 0;
+  return pool_elt_at_index (app_wrk->local_sessions, session_index);
+}
+
+local_session_t *
+app_worker_get_local_session_from_handle (session_handle_t handle)
+{
+  app_worker_t *server_wrk;
+  u32 session_index, server_wrk_index;
+  local_session_parse_handle (handle, &server_wrk_index, &session_index);
+  server_wrk = app_worker_get_if_valid (server_wrk_index);
+  if (!server_wrk)
+    return 0;
+  return app_worker_get_local_session (server_wrk, session_index);
+}
+
+void
+app_worker_local_sessions_free (app_worker_t * app_wrk)
+{
+  u32 index, server_wrk_index, session_index;
+  u64 handle, *handles = 0;
+  app_worker_t *server_wrk;
+  segment_manager_t *sm;
+  local_session_t *ls;
+  int i;
+
+  /*
+   * Local sessions
+   */
+  if (app_wrk->local_sessions)
+    {
+      /* *INDENT-OFF* */
+      pool_foreach (ls, app_wrk->local_sessions, ({
+	app_worker_local_session_disconnect (app_wrk->wrk_index, ls);
+      }));
+      /* *INDENT-ON* */
+    }
+
+  /*
+   * Local connects
+   */
+  vec_reset_length (handles);
+  /* *INDENT-OFF* */
+  hash_foreach (handle, index, app_wrk->local_connects, ({
+    vec_add1 (handles, handle);
+  }));
+  /* *INDENT-ON* */
+
+  for (i = 0; i < vec_len (handles); i++)
+    {
+      application_client_local_connect_key_parse (handles[i],
+						  &server_wrk_index,
+						  &session_index);
+      server_wrk = app_worker_get_if_valid (server_wrk_index);
+      if (server_wrk)
+	{
+	  ls = app_worker_get_local_session (server_wrk, session_index);
+	  app_worker_local_session_disconnect (app_wrk->wrk_index, ls);
+	}
+    }
+
+  sm = segment_manager_get (app_wrk->local_segment_manager);
+  sm->app_wrk_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
+  segment_manager_del (sm);
+}
+
+app_worker_t *
+app_worker_alloc (application_t * app)
+{
+  app_worker_t *app_wrk;
+  pool_get (app_workers, app_wrk);
+  clib_memset (app_wrk, 0, sizeof (*app_wrk));
+  app_wrk->wrk_index = app_wrk - app_workers;
+  app_wrk->app_index = app->app_index;
+  app_wrk->wrk_map_index = ~0;
+  app_wrk->connects_seg_manager = APP_INVALID_SEGMENT_MANAGER_INDEX;
+  app_wrk->first_segment_manager = APP_INVALID_SEGMENT_MANAGER_INDEX;
+  app_wrk->local_segment_manager = APP_INVALID_SEGMENT_MANAGER_INDEX;
+  APP_DBG ("New app %v worker %u", app_get_name (app), app_wrk->wrk_index);
+  return app_wrk;
+}
+
+app_worker_t *
+app_worker_get (u32 wrk_index)
+{
+  return pool_elt_at_index (app_workers, wrk_index);
+}
+
+app_worker_t *
+app_worker_get_if_valid (u32 wrk_index)
+{
+  if (pool_is_free_index (app_workers, wrk_index))
+    return 0;
+  return pool_elt_at_index (app_workers, wrk_index);
+}
+
+void
+app_worker_free (app_worker_t * app_wrk)
+{
+  application_t *app = application_get (app_wrk->app_index);
+  vnet_unbind_args_t _a, *a = &_a;
+  u64 handle, *handles = 0;
+  segment_manager_t *sm;
+  u32 sm_index;
+  int i;
+
+  /*
+   *  Listener cleanup
+   */
+
+  /* *INDENT-OFF* */
+  hash_foreach (handle, sm_index, app_wrk->listeners_table,
+  ({
+    vec_add1 (handles, handle);
+    sm = segment_manager_get (sm_index);
+    sm->app_wrk_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
+  }));
+  /* *INDENT-ON* */
+
+  for (i = 0; i < vec_len (handles); i++)
+    {
+      a->app_index = app->app_index;
+      a->wrk_map_index = app_wrk->wrk_map_index;
+      a->handle = handles[i];
+      /* seg manager is removed when unbind completes */
+      vnet_unbind (a);
+    }
+
+  /*
+   * Connects segment manager cleanup
+   */
+
+  if (app_wrk->connects_seg_manager != APP_INVALID_SEGMENT_MANAGER_INDEX)
+    {
+      sm = segment_manager_get (app_wrk->connects_seg_manager);
+      sm->app_wrk_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
+      segment_manager_init_del (sm);
+    }
+
+  /* If first segment manager is used by a listener */
+  if (app_wrk->first_segment_manager != APP_INVALID_SEGMENT_MANAGER_INDEX
+      && app_wrk->first_segment_manager != app_wrk->connects_seg_manager)
+    {
+      sm = segment_manager_get (app_wrk->first_segment_manager);
+      sm->first_is_protected = 0;
+      sm->app_wrk_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
+      /* .. and has no fifos, e.g. it might be used for redirected sessions,
+       * remove it */
+      if (!segment_manager_has_fifos (sm))
+	segment_manager_del (sm);
+    }
+
+  /*
+   * Local sessions
+   */
+  app_worker_local_sessions_free (app_wrk);
+
+  pool_put (app_workers, app_wrk);
+  if (CLIB_DEBUG)
+    clib_memset (app_wrk, 0xfe, sizeof (*app_wrk));
+}
+
+application_t *
+app_worker_get_app (u32 wrk_index)
+{
+  app_worker_t *app_wrk;
+  app_wrk = app_worker_get_if_valid (wrk_index);
+  if (!app_wrk)
+    return 0;
+  return application_get_if_valid (app_wrk->app_index);
+}
+
+static segment_manager_t *
+app_worker_alloc_segment_manager (app_worker_t * app_wrk)
+{
+  segment_manager_t *sm = 0;
+
+  /* If the first segment manager is not in use, don't allocate a new one */
+  if (app_wrk->first_segment_manager != APP_INVALID_SEGMENT_MANAGER_INDEX
+      && app_wrk->first_segment_manager_in_use == 0)
+    {
+      sm = segment_manager_get (app_wrk->first_segment_manager);
+      app_wrk->first_segment_manager_in_use = 1;
+      return sm;
+    }
+
+  sm = segment_manager_new ();
+  sm->app_wrk_index = app_wrk->wrk_index;
+
+  return sm;
+}
+
+int
+app_worker_start_listen (app_worker_t * app_wrk, session_t * ls)
+{
+  segment_manager_t *sm;
+
+  /* Allocate segment manager. All sessions derived out of a listen session
+   * have fifos allocated by the same segment manager. */
+  if (!(sm = app_worker_alloc_segment_manager (app_wrk)))
+    return -1;
+
+  /* Add to app's listener table. Useful to find all child listeners
+   * when app goes down, although, just for unbinding this is not needed */
+  hash_set (app_wrk->listeners_table, listen_session_get_handle (ls),
+	    segment_manager_index (sm));
+
+  if (!ls->rx_fifo
+      && session_transport_service_type (ls) == TRANSPORT_SERVICE_CL)
+    {
+      if (session_alloc_fifos (sm, ls))
+	return -1;
+    }
+  return 0;
+}
+
+int
+app_worker_stop_listen (app_worker_t * app_wrk, session_handle_t handle)
+{
+  segment_manager_t *sm;
+  uword *sm_indexp;
+
+  sm_indexp = hash_get (app_wrk->listeners_table, handle);
+  if (PREDICT_FALSE (!sm_indexp))
+    {
+      clib_warning ("listener handle was removed %llu!", handle);
+      return -1;
+    }
+
+  sm = segment_manager_get (*sm_indexp);
+  if (app_wrk->first_segment_manager == *sm_indexp)
+    {
+      /* Delete sessions but don't remove segment manager */
+      app_wrk->first_segment_manager_in_use = 0;
+      segment_manager_del_sessions (sm);
+    }
+  else
+    {
+      segment_manager_init_del (sm);
+    }
+  hash_unset (app_wrk->listeners_table, handle);
+
+  return 0;
+}
+
+int
+app_worker_own_session (app_worker_t * app_wrk, session_t * s)
+{
+  segment_manager_t *sm;
+  svm_fifo_t *rxf, *txf;
+
+  if (s->session_state == SESSION_STATE_LISTENING)
+    return application_change_listener_owner (s, app_wrk);
+
+  s->app_wrk_index = app_wrk->wrk_index;
+
+  rxf = s->rx_fifo;
+  txf = s->tx_fifo;
+
+  if (!rxf || !txf)
+    return 0;
+
+  s->rx_fifo = 0;
+  s->tx_fifo = 0;
+
+  sm = app_worker_get_or_alloc_connect_segment_manager (app_wrk);
+  if (session_alloc_fifos (sm, s))
+    return -1;
+
+  if (!svm_fifo_is_empty (rxf))
+    {
+      clib_memcpy_fast (s->rx_fifo->data, rxf->data, rxf->nitems);
+      s->rx_fifo->head = rxf->head;
+      s->rx_fifo->tail = rxf->tail;
+      s->rx_fifo->cursize = rxf->cursize;
+    }
+
+  if (!svm_fifo_is_empty (txf))
+    {
+      clib_memcpy_fast (s->tx_fifo->data, txf->data, txf->nitems);
+      s->tx_fifo->head = txf->head;
+      s->tx_fifo->tail = txf->tail;
+      s->tx_fifo->cursize = txf->cursize;
+    }
+
+  segment_manager_dealloc_fifos (rxf->segment_index, rxf, txf);
+
+  return 0;
+}
+
+int
+app_worker_open_session (app_worker_t * app, session_endpoint_t * sep,
+			 u32 api_context)
+{
+  int rv;
+
+  /* Make sure we have a segment manager for connects */
+  app_worker_alloc_connects_segment_manager (app);
+
+  if ((rv = session_open (app->wrk_index, sep, api_context)))
+    return rv;
+
+  return 0;
+}
+
+int
+app_worker_alloc_connects_segment_manager (app_worker_t * app_wrk)
+{
+  segment_manager_t *sm;
+
+  if (app_wrk->connects_seg_manager == APP_INVALID_SEGMENT_MANAGER_INDEX)
+    {
+      sm = app_worker_alloc_segment_manager (app_wrk);
+      if (sm == 0)
+	return -1;
+      app_wrk->connects_seg_manager = segment_manager_index (sm);
+    }
+  return 0;
+}
+
+segment_manager_t *
+app_worker_get_connect_segment_manager (app_worker_t * app)
+{
+  ASSERT (app->connects_seg_manager != (u32) ~ 0);
+  return segment_manager_get (app->connects_seg_manager);
+}
+
+segment_manager_t *
+app_worker_get_or_alloc_connect_segment_manager (app_worker_t * app_wrk)
+{
+  if (app_wrk->connects_seg_manager == (u32) ~ 0)
+    app_worker_alloc_connects_segment_manager (app_wrk);
+  return segment_manager_get (app_wrk->connects_seg_manager);
+}
+
+segment_manager_t *
+app_worker_get_listen_segment_manager (app_worker_t * app,
+				       session_t * listener)
+{
+  uword *smp;
+  smp = hash_get (app->listeners_table, listen_session_get_handle (listener));
+  ASSERT (smp != 0);
+  return segment_manager_get (*smp);
+}
+
+session_t *
+app_worker_first_listener (app_worker_t * app, u8 fib_proto,
+			   u8 transport_proto)
+{
+  session_t *listener;
+  u64 handle;
+  u32 sm_index;
+  u8 sst;
+
+  sst = session_type_from_proto_and_ip (transport_proto,
+					fib_proto == FIB_PROTOCOL_IP4);
+
+  /* *INDENT-OFF* */
+   hash_foreach (handle, sm_index, app->listeners_table, ({
+     listener = listen_session_get_from_handle (handle);
+     if (listener->session_type == sst
+	 && listener->enqueue_epoch != SESSION_PROXY_LISTENER_INDEX)
+       return listener;
+   }));
+  /* *INDENT-ON* */
+
+  return 0;
+}
+
+session_t *
+app_worker_proxy_listener (app_worker_t * app, u8 fib_proto,
+			   u8 transport_proto)
+{
+  session_t *listener;
+  u64 handle;
+  u32 sm_index;
+  u8 sst;
+
+  sst = session_type_from_proto_and_ip (transport_proto,
+					fib_proto == FIB_PROTOCOL_IP4);
+
+  /* *INDENT-OFF* */
+   hash_foreach (handle, sm_index, app->listeners_table, ({
+     listener = listen_session_get_from_handle (handle);
+     if (listener->session_type == sst
+	 && listener->enqueue_epoch == SESSION_PROXY_LISTENER_INDEX)
+       return listener;
+   }));
+  /* *INDENT-ON* */
+
+  return 0;
+}
+
+/**
+ * Send an API message to the external app, to map new segment
+ */
+int
+app_worker_add_segment_notify (u32 app_wrk_index, u64 segment_handle)
+{
+  app_worker_t *app_wrk = app_worker_get (app_wrk_index);
+  application_t *app = application_get (app_wrk->app_index);
+  return app->cb_fns.add_segment_callback (app_wrk->api_client_index,
+					   segment_handle);
+}
+
+u8
+app_worker_application_is_builtin (app_worker_t * app_wrk)
+{
+  return app_wrk->app_is_builtin;
+}
+
+static inline int
+app_enqueue_evt (svm_msg_q_t * mq, svm_msg_q_msg_t * msg, u8 lock)
+{
+  if (PREDICT_FALSE (svm_msg_q_is_full (mq)))
+    {
+      clib_warning ("evt q full");
+      svm_msg_q_free_msg (mq, msg);
+      if (lock)
+	svm_msg_q_unlock (mq);
+      return -1;
+    }
+
+  if (lock)
+    {
+      svm_msg_q_add_and_unlock (mq, msg);
+      return 0;
+    }
+
+  /* Even when not locking the ring, we must wait for queue mutex */
+  if (svm_msg_q_add (mq, msg, SVM_Q_WAIT))
+    {
+      clib_warning ("msg q add returned");
+      return -1;
+    }
+  return 0;
+}
+
+static inline int
+app_send_io_evt_rx (app_worker_t * app_wrk, session_t * s, u8 lock)
+{
+  session_event_t *evt;
+  svm_msg_q_msg_t msg;
+  svm_msg_q_t *mq;
+
+  if (PREDICT_FALSE (s->session_state != SESSION_STATE_READY
+		     && s->session_state != SESSION_STATE_LISTENING))
+    {
+      /* Session is closed so app will never clean up. Flush rx fifo */
+      if (s->session_state == SESSION_STATE_CLOSED)
+	svm_fifo_dequeue_drop_all (s->rx_fifo);
+      return 0;
+    }
+
+  if (app_worker_application_is_builtin (app_wrk))
+    {
+      application_t *app = application_get (app_wrk->app_index);
+      return app->cb_fns.builtin_app_rx_callback (s);
+    }
+
+  if (svm_fifo_has_event (s->rx_fifo) || svm_fifo_is_empty (s->rx_fifo))
+    return 0;
+
+  mq = app_wrk->event_queue;
+  if (lock)
+    svm_msg_q_lock (mq);
+
+  if (PREDICT_FALSE (svm_msg_q_ring_is_full (mq, SESSION_MQ_IO_EVT_RING)))
+    {
+      clib_warning ("evt q rings full");
+      if (lock)
+	svm_msg_q_unlock (mq);
+      return -1;
+    }
+
+  msg = svm_msg_q_alloc_msg_w_ring (mq, SESSION_MQ_IO_EVT_RING);
+  ASSERT (!svm_msg_q_msg_is_invalid (&msg));
+
+  evt = (session_event_t *) svm_msg_q_msg_data (mq, &msg);
+  evt->fifo = s->rx_fifo;
+  evt->event_type = FIFO_EVENT_APP_RX;
+
+  (void) svm_fifo_set_event (s->rx_fifo);
+
+  if (app_enqueue_evt (mq, &msg, lock))
+    return -1;
+  return 0;
+}
+
+static inline int
+app_send_io_evt_tx (app_worker_t * app_wrk, session_t * s, u8 lock)
+{
+  svm_msg_q_t *mq;
+  session_event_t *evt;
+  svm_msg_q_msg_t msg;
+
+  if (app_worker_application_is_builtin (app_wrk))
+    return 0;
+
+  mq = app_wrk->event_queue;
+  if (lock)
+    svm_msg_q_lock (mq);
+
+  if (PREDICT_FALSE (svm_msg_q_ring_is_full (mq, SESSION_MQ_IO_EVT_RING)))
+    {
+      clib_warning ("evt q rings full");
+      if (lock)
+	svm_msg_q_unlock (mq);
+      return -1;
+    }
+
+  msg = svm_msg_q_alloc_msg_w_ring (mq, SESSION_MQ_IO_EVT_RING);
+  ASSERT (!svm_msg_q_msg_is_invalid (&msg));
+
+  evt = (session_event_t *) svm_msg_q_msg_data (mq, &msg);
+  evt->event_type = FIFO_EVENT_APP_TX;
+  evt->fifo = s->tx_fifo;
+
+  return app_enqueue_evt (mq, &msg, lock);
+}
+
+/* *INDENT-OFF* */
+typedef int (app_send_evt_handler_fn) (app_worker_t *app,
+				       session_t *s,
+				       u8 lock);
+static app_send_evt_handler_fn * const app_send_evt_handler_fns[3] = {
+    app_send_io_evt_rx,
+    0,
+    app_send_io_evt_tx,
+};
+/* *INDENT-ON* */
+
+/**
+ * Send event to application
+ *
+ * Logic from queue perspective is non-blocking. If there's
+ * not enough space to enqueue a message, we return.
+ */
+int
+app_worker_send_event (app_worker_t * app, session_t * s, u8 evt_type)
+{
+  ASSERT (app && evt_type <= FIFO_EVENT_APP_TX);
+  return app_send_evt_handler_fns[evt_type] (app, s, 0 /* lock */ );
+}
+
+/**
+ * Send event to application
+ *
+ * Logic from queue perspective is blocking. However, if queue is full,
+ * we return.
+ */
+int
+app_worker_lock_and_send_event (app_worker_t * app, session_t * s,
+				u8 evt_type)
+{
+  return app_send_evt_handler_fns[evt_type] (app, s, 1 /* lock */ );
+}
+
+segment_manager_t *
+app_worker_get_local_segment_manager (app_worker_t * app_worker)
+{
+  return segment_manager_get (app_worker->local_segment_manager);
+}
+
+segment_manager_t *
+app_worker_get_local_segment_manager_w_session (app_worker_t * app_wrk,
+						local_session_t * ls)
+{
+  session_t *listener;
+  if (application_local_session_listener_has_transport (ls))
+    {
+      listener = listen_session_get (ls->listener_index);
+      return app_worker_get_listen_segment_manager (app_wrk, listener);
+    }
+  return segment_manager_get (app_wrk->local_segment_manager);
+}
+
+int
+app_worker_local_session_cleanup (app_worker_t * client_wrk,
+				  app_worker_t * server_wrk,
+				  local_session_t * ls)
+{
+  svm_fifo_segment_private_t *seg;
+  session_t *listener;
+  segment_manager_t *sm;
+  u64 client_key;
+  u8 has_transport;
+
+  /* Retrieve listener transport type as it is the one that decides where
+   * the fifos are allocated */
+  has_transport = application_local_session_listener_has_transport (ls);
+  if (!has_transport)
+    sm = app_worker_get_local_segment_manager_w_session (server_wrk, ls);
+  else
+    {
+      listener = listen_session_get (ls->listener_index);
+      sm = app_worker_get_listen_segment_manager (server_wrk, listener);
+    }
+
+  seg = segment_manager_get_segment (sm, ls->svm_segment_index);
+  if (client_wrk)
+    {
+      client_key = application_client_local_connect_key (ls);
+      hash_unset (client_wrk->local_connects, client_key);
+    }
+
+  if (!has_transport)
+    {
+      application_t *server = application_get (server_wrk->app_index);
+      u64 segment_handle = segment_manager_segment_handle (sm, seg);
+      server->cb_fns.del_segment_callback (server_wrk->api_client_index,
+					   segment_handle);
+      if (client_wrk)
+	{
+	  application_t *client = application_get (client_wrk->app_index);
+	  client->cb_fns.del_segment_callback (client_wrk->api_client_index,
+					       segment_handle);
+	}
+      segment_manager_del_segment (sm, seg);
+    }
+
+  app_worker_local_session_free (server_wrk, ls);
+
+  return 0;
+}
+
+static void
+application_local_session_fix_eventds (svm_msg_q_t * sq, svm_msg_q_t * cq)
+{
+  int fd;
+
+  /*
+   * segment manager initializes only the producer eventds, since vpp is
+   * typically the producer. But for local sessions, we also pass to the
+   * apps the mqs they listen on for events from peer apps, so they are also
+   * consumer fds.
+   */
+  fd = svm_msg_q_get_producer_eventfd (sq);
+  svm_msg_q_set_consumer_eventfd (sq, fd);
+  fd = svm_msg_q_get_producer_eventfd (cq);
+  svm_msg_q_set_consumer_eventfd (cq, fd);
+}
+
+int
+app_worker_local_session_connect (app_worker_t * client_wrk,
+				  app_worker_t * server_wrk,
+				  local_session_t * ll, u32 opaque)
+{
+  u32 seg_size, evt_q_sz, evt_q_elts, margin = 16 << 10;
+  u32 round_rx_fifo_sz, round_tx_fifo_sz, sm_index;
+  segment_manager_properties_t *props, *cprops;
+  int rv, has_transport, seg_index;
+  svm_fifo_segment_private_t *seg;
+  application_t *server, *client;
+  segment_manager_t *sm;
+  local_session_t *ls;
+  svm_msg_q_t *sq, *cq;
+  u64 segment_handle;
+
+  ls = app_worker_local_session_alloc (server_wrk);
+  server = application_get (server_wrk->app_index);
+  client = application_get (client_wrk->app_index);
+
+  props = application_segment_manager_properties (server);
+  cprops = application_segment_manager_properties (client);
+  evt_q_elts = props->evt_q_size + cprops->evt_q_size;
+  evt_q_sz = segment_manager_evt_q_expected_size (evt_q_elts);
+  round_rx_fifo_sz = 1 << max_log2 (props->rx_fifo_size);
+  round_tx_fifo_sz = 1 << max_log2 (props->tx_fifo_size);
+  seg_size = round_rx_fifo_sz + round_tx_fifo_sz + evt_q_sz + margin;
+
+  has_transport = session_has_transport ((session_t *) ll);
+  if (!has_transport)
+    {
+      /* Local sessions don't have backing transport */
+      ls->port = ll->port;
+      sm = app_worker_get_local_segment_manager (server_wrk);
+    }
+  else
+    {
+      session_t *sl = (session_t *) ll;
+      transport_connection_t *tc;
+      tc = listen_session_get_transport (sl);
+      ls->port = tc->lcl_port;
+      sm = app_worker_get_listen_segment_manager (server_wrk, sl);
+    }
+
+  seg_index = segment_manager_add_segment (sm, seg_size);
+  if (seg_index < 0)
+    {
+      clib_warning ("failed to add new cut-through segment");
+      return seg_index;
+    }
+  seg = segment_manager_get_segment_w_lock (sm, seg_index);
+  sq = segment_manager_alloc_queue (seg, props);
+  cq = segment_manager_alloc_queue (seg, cprops);
+
+  if (props->use_mq_eventfd)
+    application_local_session_fix_eventds (sq, cq);
+
+  ls->server_evt_q = pointer_to_uword (sq);
+  ls->client_evt_q = pointer_to_uword (cq);
+  rv = segment_manager_try_alloc_fifos (seg, props->rx_fifo_size,
+					props->tx_fifo_size,
+					&ls->rx_fifo, &ls->tx_fifo);
+  if (rv)
+    {
+      clib_warning ("failed to add fifos in cut-through segment");
+      segment_manager_segment_reader_unlock (sm);
+      goto failed;
+    }
+  sm_index = segment_manager_index (sm);
+  ls->rx_fifo->ct_session_index = ls->session_index;
+  ls->tx_fifo->ct_session_index = ls->session_index;
+  ls->rx_fifo->segment_manager = sm_index;
+  ls->tx_fifo->segment_manager = sm_index;
+  ls->rx_fifo->segment_index = seg_index;
+  ls->tx_fifo->segment_index = seg_index;
+  ls->svm_segment_index = seg_index;
+  ls->listener_index = ll->session_index;
+  ls->client_wrk_index = client_wrk->wrk_index;
+  ls->client_opaque = opaque;
+  ls->listener_session_type = ll->session_type;
+  ls->session_state = SESSION_STATE_READY;
+
+  segment_handle = segment_manager_segment_handle (sm, seg);
+  if ((rv = server->cb_fns.add_segment_callback (server_wrk->api_client_index,
+						 segment_handle)))
+    {
+      clib_warning ("failed to notify server of new segment");
+      segment_manager_segment_reader_unlock (sm);
+      goto failed;
+    }
+  segment_manager_segment_reader_unlock (sm);
+  if ((rv = server->cb_fns.session_accept_callback ((session_t *) ls)))
+    {
+      clib_warning ("failed to send accept cut-through notify to server");
+      goto failed;
+    }
+  if (server->flags & APP_OPTIONS_FLAGS_IS_BUILTIN)
+    app_worker_local_session_connect_notify (ls);
+
+  return 0;
+
+failed:
+  if (!has_transport)
+    segment_manager_del_segment (sm, seg);
+  return rv;
+}
+
+int
+app_worker_local_session_connect_notify (local_session_t * ls)
+{
+  svm_fifo_segment_private_t *seg;
+  app_worker_t *client_wrk, *server_wrk;
+  segment_manager_t *sm;
+  application_t *client;
+  int rv, is_fail = 0;
+  u64 segment_handle;
+  u64 client_key;
+
+  client_wrk = app_worker_get (ls->client_wrk_index);
+  server_wrk = app_worker_get (ls->app_wrk_index);
+  client = application_get (client_wrk->app_index);
+
+  sm = app_worker_get_local_segment_manager_w_session (server_wrk, ls);
+  seg = segment_manager_get_segment_w_lock (sm, ls->svm_segment_index);
+  segment_handle = segment_manager_segment_handle (sm, seg);
+  if ((rv = client->cb_fns.add_segment_callback (client_wrk->api_client_index,
+						 segment_handle)))
+    {
+      clib_warning ("failed to notify client %u of new segment",
+		    ls->client_wrk_index);
+      segment_manager_segment_reader_unlock (sm);
+      app_worker_local_session_disconnect (ls->client_wrk_index, ls);
+      is_fail = 1;
+    }
+  else
+    {
+      segment_manager_segment_reader_unlock (sm);
+    }
+
+  client->cb_fns.session_connected_callback (client_wrk->wrk_index,
+					     ls->client_opaque,
+					     (session_t *) ls, is_fail);
+
+  client_key = application_client_local_connect_key (ls);
+  hash_set (client_wrk->local_connects, client_key, client_key);
+  return 0;
+}
+
+int
+app_worker_local_session_disconnect (u32 app_index, local_session_t * ls)
+{
+  app_worker_t *client_wrk, *server_wrk;
+  u8 is_server = 0, is_client = 0;
+  application_t *app;
+
+  app = application_get_if_valid (app_index);
+  if (!app)
+    return 0;
+
+  client_wrk = app_worker_get_if_valid (ls->client_wrk_index);
+  server_wrk = app_worker_get (ls->app_wrk_index);
+
+  if (server_wrk->app_index == app_index)
+    is_server = 1;
+  else if (client_wrk && client_wrk->app_index == app_index)
+    is_client = 1;
+
+  if (!is_server && !is_client)
+    {
+      clib_warning ("app %u is neither client nor server for session 0x%lx",
+		    app_index, application_local_session_handle (ls));
+      return VNET_API_ERROR_INVALID_VALUE;
+    }
+
+  if (ls->session_state == SESSION_STATE_CLOSED)
+    return app_worker_local_session_cleanup (client_wrk, server_wrk, ls);
+
+  if (app_index == ls->client_wrk_index)
+    {
+      mq_send_local_session_disconnected_cb (ls->app_wrk_index, ls);
+    }
+  else
+    {
+      if (!client_wrk)
+	{
+	  return app_worker_local_session_cleanup (client_wrk, server_wrk,
+						   ls);
+	}
+      else if (ls->session_state < SESSION_STATE_READY)
+	{
+	  application_t *client = application_get (client_wrk->app_index);
+	  client->cb_fns.session_connected_callback (client_wrk->wrk_index,
+						     ls->client_opaque,
+						     (session_t *) ls,
+						     1 /* is_fail */ );
+	  ls->session_state = SESSION_STATE_CLOSED;
+	  return app_worker_local_session_cleanup (client_wrk, server_wrk,
+						   ls);
+	}
+      else
+	{
+	  mq_send_local_session_disconnected_cb (client_wrk->wrk_index, ls);
+	}
+    }
+
+  ls->session_state = SESSION_STATE_CLOSED;
+
+  return 0;
+}
+
+int
+app_worker_local_session_disconnect_w_index (u32 app_wrk_index, u32 ls_index)
+{
+  app_worker_t *app_wrk;
+  local_session_t *ls;
+  app_wrk = app_worker_get (app_wrk_index);
+  ls = app_worker_get_local_session (app_wrk, ls_index);
+  return app_worker_local_session_disconnect (app_wrk_index, ls);
+}
+
+u8 *
+format_app_worker_listener (u8 * s, va_list * args)
+{
+  app_worker_t *app_wrk = va_arg (*args, app_worker_t *);
+  u64 handle = va_arg (*args, u64);
+  u32 sm_index = va_arg (*args, u32);
+  int verbose = va_arg (*args, int);
+  session_t *listener;
+  const u8 *app_name;
+  u8 *str;
+
+  if (!app_wrk)
+    {
+      if (verbose)
+	s = format (s, "%-40s%-25s%=10s%-15s%-15s%-10s", "Connection", "App",
+		    "Wrk", "API Client", "ListenerID", "SegManager");
+      else
+	s = format (s, "%-40s%-25s%=10s", "Connection", "App", "Wrk");
+
+      return s;
+    }
+
+  app_name = application_name_from_index (app_wrk->app_index);
+  listener = listen_session_get_from_handle (handle);
+  str = format (0, "%U", format_stream_session, listener, verbose);
+
+  if (verbose)
+    {
+      char buf[32];
+      sprintf (buf, "%u(%u)", app_wrk->wrk_map_index, app_wrk->wrk_index);
+      s = format (s, "%-40s%-25s%=10s%-15u%-15u%-10u", str, app_name,
+		  buf, app_wrk->api_client_index, handle, sm_index);
+    }
+  else
+    s = format (s, "%-40s%-25s%=10u", str, app_name, app_wrk->wrk_map_index);
+
+  return s;
+}
+
+u8 *
+format_app_worker (u8 * s, va_list * args)
+{
+  app_worker_t *app_wrk = va_arg (*args, app_worker_t *);
+  u32 indent = 1;
+
+  s = format (s, "%U wrk-index %u app-index %u map-index %u "
+	      "api-client-index %d\n", format_white_space, indent,
+	      app_wrk->wrk_index, app_wrk->app_index, app_wrk->wrk_map_index,
+	      app_wrk->api_client_index);
+  return s;
+}
+
+void
+app_worker_format_connects (app_worker_t * app_wrk, int verbose)
+{
+  svm_fifo_segment_private_t *fifo_segment;
+  vlib_main_t *vm = vlib_get_main ();
+  segment_manager_t *sm;
+  const u8 *app_name;
+  u8 *s = 0;
+
+  /* Header */
+  if (!app_wrk)
+    {
+      if (verbose)
+	vlib_cli_output (vm, "%-40s%-20s%-15s%-10s", "Connection", "App",
+			 "API Client", "SegManager");
+      else
+	vlib_cli_output (vm, "%-40s%-20s", "Connection", "App");
+      return;
+    }
+
+  if (app_wrk->connects_seg_manager == (u32) ~ 0)
+    return;
+
+  app_name = application_name_from_index (app_wrk->app_index);
+
+  /* Across all fifo segments */
+  sm = segment_manager_get (app_wrk->connects_seg_manager);
+
+  /* *INDENT-OFF* */
+  segment_manager_foreach_segment_w_lock (fifo_segment, sm, ({
+    svm_fifo_t *fifo;
+    u8 *str;
+
+    fifo = svm_fifo_segment_get_fifo_list (fifo_segment);
+    while (fifo)
+      {
+        u32 session_index, thread_index;
+        session_t *session;
+
+        session_index = fifo->master_session_index;
+        thread_index = fifo->master_thread_index;
+
+        session = session_get (session_index, thread_index);
+        str = format (0, "%U", format_stream_session, session, verbose);
+
+        if (verbose)
+          s = format (s, "%-40s%-20s%-15u%-10u", str, app_name,
+                      app_wrk->api_client_index, app_wrk->connects_seg_manager);
+        else
+          s = format (s, "%-40s%-20s", str, app_name);
+
+        vlib_cli_output (vm, "%v", s);
+        vec_reset_length (s);
+        vec_free (str);
+
+        fifo = fifo->next;
+      }
+    vec_free (s);
+  }));
+  /* *INDENT-ON* */
+}
+
+void
+app_worker_format_local_sessions (app_worker_t * app_wrk, int verbose)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  local_session_t *ls;
+  transport_proto_t tp;
+  u8 *conn = 0;
+
+  /* Header */
+  if (app_wrk == 0)
+    {
+      vlib_cli_output (vm, "%-40s%-15s%-20s", "Connection", "ServerApp",
+		       "ClientApp");
+      return;
+    }
+
+  if (!pool_elts (app_wrk->local_sessions)
+      && !pool_elts (app_wrk->local_connects))
+    return;
+
+  /* *INDENT-OFF* */
+  pool_foreach (ls, app_wrk->local_sessions, ({
+    tp = session_type_transport_proto(ls->listener_session_type);
+    conn = format (0, "[L][%U] *:%u", format_transport_proto_short, tp,
+                   ls->port);
+    vlib_cli_output (vm, "%-40v%-15u%-20u", conn, ls->app_wrk_index,
+                     ls->client_wrk_index);
+    vec_reset_length (conn);
+  }));
+  /* *INDENT-ON* */
+
+  vec_free (conn);
+}
+
+void
+app_worker_format_local_connects (app_worker_t * app, int verbose)
+{
+  vlib_main_t *vm = vlib_get_main ();
+  u32 app_wrk_index, session_index;
+  app_worker_t *server_wrk;
+  local_session_t *ls;
+  u64 client_key;
+  u64 value;
+
+  /* Header */
+  if (app == 0)
+    {
+      if (verbose)
+	vlib_cli_output (vm, "%-40s%-15s%-20s%-10s", "Connection", "App",
+			 "Peer App", "SegManager");
+      else
+	vlib_cli_output (vm, "%-40s%-15s%-20s", "Connection", "App",
+			 "Peer App");
+      return;
+    }
+
+  if (!app->local_connects)
+    return;
+
+  /* *INDENT-OFF* */
+  hash_foreach (client_key, value, app->local_connects, ({
+    application_client_local_connect_key_parse (client_key, &app_wrk_index,
+                                                &session_index);
+    server_wrk = app_worker_get (app_wrk_index);
+    ls = app_worker_get_local_session (server_wrk, session_index);
+    vlib_cli_output (vm, "%-40s%-15s%-20s", "TODO", ls->app_wrk_index,
+                     ls->client_wrk_index);
+  }));
+  /* *INDENT-ON* */
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/session/segment_manager.c b/src/vnet/session/segment_manager.c
index a4438c7aeea..638f078e20d 100644
--- a/src/vnet/session/segment_manager.c
+++ b/src/vnet/session/segment_manager.c
@@ -399,7 +399,7 @@ segment_manager_del_sessions (segment_manager_t * sm)
 	if (fifo->ct_session_index != SVM_FIFO_INVALID_SESSION_INDEX)
 	  {
 	    svm_fifo_t *next = fifo->next;
-	    application_local_session_disconnect_w_index (sm->app_wrk_index,
+	    app_worker_local_session_disconnect_w_index (sm->app_wrk_index,
 	                                                  fifo->ct_session_index);
 	    fifo = next;
 	    continue;
diff --git a/src/vnet/session/session_api.c b/src/vnet/session/session_api.c
index 6a0d77eed12..bd809367ce5 100755
--- a/src/vnet/session/session_api.c
+++ b/src/vnet/session/session_api.c
@@ -1144,14 +1144,14 @@ vl_api_accept_session_reply_t_handler (vl_api_accept_session_reply_t * mp)
 
   if (session_handle_is_local (mp->handle))
     {
-      ls = application_get_local_session_from_handle (mp->handle);
+      ls = app_worker_get_local_session_from_handle (mp->handle);
       if (!ls || ls->app_wrk_index != mp->context)
 	{
 	  clib_warning ("server %u doesn't own local handle %llu",
 			mp->context, mp->handle);
 	  return;
 	}
-      if (application_local_session_connect_notify (ls))
+      if (app_worker_local_session_connect_notify (ls))
 	return;
       ls->session_state = SESSION_STATE_READY;
     }
diff --git a/src/vnet/session/session_node.c b/src/vnet/session/session_node.c
index fe7f652a98a..fa33ad37f1e 100644
--- a/src/vnet/session/session_node.c
+++ b/src/vnet/session/session_node.c
@@ -45,7 +45,7 @@ session_mq_accepted_reply_handler (void *data)
 
   if (session_handle_is_local (mp->handle))
     {
-      ls = application_get_local_session_from_handle (mp->handle);
+      ls = app_worker_get_local_session_from_handle (mp->handle);
       if (!ls)
 	{
 	  clib_warning ("unknown local handle 0x%lx", mp->handle);
@@ -58,7 +58,7 @@ session_mq_accepted_reply_handler (void *data)
 			mp->context, mp->handle);
 	  return;
 	}
-      if (application_local_session_connect_notify (ls))
+      if (app_worker_local_session_connect_notify (ls))
 	return;
       ls->session_state = SESSION_STATE_READY;
     }