session: refactor listen logic

Make app-listener the handle for app listens. Consequently transport and
local listen sessions are now associated to the app-listener.

Change-Id: I9397a26d42cccb100970b6b4794c15bac2e11465
Signed-off-by: Florin Coras <fcoras@cisco.com>

9 files changed, 586 insertions, 634 deletions

diff --git a/src/vnet/session/application.c b/src/vnet/session/application.c
index 3380d0bca4a..763ab351b17 100644
--- a/src/vnet/session/application.c
+++ b/src/vnet/session/application.c
@@ -20,6 +20,16 @@
 
 static app_main_t app_main;
 
+static void
+application_local_listener_session_endpoint (local_session_t * ll,
+					     session_endpoint_t * sep)
+{
+  sep->transport_proto =
+    session_type_transport_proto (ll->listener_session_type);
+  sep->port = ll->port;
+  sep->is_ip4 = ll->listener_session_type & 1;
+}
+
 static app_listener_t *
 app_listener_alloc (application_t * app)
 {
@@ -27,10 +37,13 @@ app_listener_alloc (application_t * app)
   pool_get (app->listeners, app_listener);
   clib_memset (app_listener, 0, sizeof (*app_listener));
   app_listener->al_index = app_listener - app->listeners;
+  app_listener->app_index = app->app_index;
+  app_listener->session_index = SESSION_INVALID_INDEX;
+  app_listener->local_index = SESSION_INVALID_INDEX;
   return app_listener;
 }
 
-static app_listener_t *
+app_listener_t *
 app_listener_get (application_t * app, u32 app_listener_index)
 {
   return pool_elt_at_index (app->listeners, app_listener_index);
@@ -45,29 +58,242 @@ app_listener_free (application_t * app, app_listener_t * app_listener)
     clib_memset (app_listener, 0xfa, sizeof (*app_listener));
 }
 
+local_session_t *
+application_local_listen_session_alloc (application_t * app)
+{
+  local_session_t *ll;
+  pool_get_zero (app->local_listen_sessions, ll);
+  ll->session_index = ll - app->local_listen_sessions;
+  ll->session_type = session_type_from_proto_and_ip (TRANSPORT_PROTO_NONE, 0);
+  ll->app_index = app->app_index;
+  return ll;
+}
+
+void
+application_local_listen_session_free (application_t * app,
+				       local_session_t * ll)
+{
+  pool_put (app->local_listen_sessions, ll);
+  if (CLIB_DEBUG)
+    clib_memset (ll, 0xfb, sizeof (*ll));
+}
+
+static u32
+app_listener_id (app_listener_t * al)
+{
+  ASSERT (al->app_index < 1 << 16 && al->al_index < 1 << 16);
+  return (al->app_index << 16 | al->al_index);
+}
+
+session_handle_t
+app_listener_handle (app_listener_t * al)
+{
+  return ((u64) SESSION_LISTENER_PREFIX << 32 | (u64) app_listener_id (al));
+}
+
+static void
+app_listener_id_parse (u32 listener_id, u32 * app_index,
+		       u32 * app_listener_index)
+{
+  *app_index = listener_id >> 16;
+  *app_listener_index = listener_id & 0xFFFF;
+}
+
+void
+app_listener_handle_parse (session_handle_t handle, u32 * app_index,
+			   u32 * app_listener_index)
+{
+  app_listener_id_parse (handle & 0xFFFFFFFF, app_index, app_listener_index);
+}
+
 static app_listener_t *
-app_local_listener_alloc (application_t * app)
+app_listener_get_w_id (u32 listener_id)
+{
+  u32 app_index, app_listener_index;
+  application_t *app;
+
+  app_listener_id_parse (listener_id, &app_index, &app_listener_index);
+  app = application_get_if_valid (app_index);
+  if (!app)
+    return 0;
+  return app_listener_get (app, app_listener_index);
+}
+
+app_listener_t *
+app_listener_get_w_session (session_t * ls)
+{
+  application_t *app;
+
+  app = application_get_if_valid (ls->app_index);
+  if (!app)
+    return 0;
+  return app_listener_get (app, ls->al_index);
+}
+
+app_listener_t *
+app_listener_get_w_handle (session_handle_t handle)
+{
+
+  if (handle >> 32 != SESSION_LISTENER_PREFIX)
+    return 0;
+
+  return app_listener_get_w_id (handle & 0xFFFFFFFF);
+}
+
+app_listener_t *
+app_listener_lookup (application_t * app, session_endpoint_cfg_t * sep_ext)
+{
+  u32 table_index, fib_proto;
+  session_endpoint_t *sep;
+  session_handle_t handle;
+  local_session_t *ll;
+  session_t *ls;
+
+  sep = (session_endpoint_t *) sep_ext;
+  if (application_has_local_scope (app) && session_endpoint_is_local (sep))
+    {
+      table_index = application_local_session_table (app);
+      handle = session_lookup_endpoint_listener (table_index, sep, 1);
+      if (handle != SESSION_INVALID_HANDLE)
+	{
+	  ll = application_get_local_listener_w_handle (handle);
+	  return app_listener_get_w_session ((session_t *) ll);
+	}
+    }
+
+  fib_proto = session_endpoint_fib_proto (sep);
+  table_index = application_session_table (app, fib_proto);
+  handle = session_lookup_endpoint_listener (table_index, sep, 1);
+  if (handle != SESSION_INVALID_HANDLE)
+    {
+      ls = listen_session_get_from_handle (handle);
+      return app_listener_get_w_session ((session_t *) ls);
+    }
+
+  return 0;
+}
+
+int
+app_listener_alloc_and_init (application_t * app,
+			     session_endpoint_cfg_t * sep,
+			     app_listener_t ** listener)
 {
   app_listener_t *app_listener;
-  pool_get (app->local_listeners, app_listener);
-  clib_memset (app_listener, 0, sizeof (*app_listener));
-  app_listener->al_index = app_listener - app->local_listeners;
-  return app_listener;
+  local_session_t *ll = 0;
+  session_handle_t lh;
+  session_type_t st;
+  session_t *ls = 0;
+  int rv;
+
+  app_listener = app_listener_alloc (app);
+  st = session_type_from_proto_and_ip (sep->transport_proto, sep->is_ip4);
+
+  /*
+   * Add session endpoint to local session table. Only binds to "inaddr_any"
+   * (i.e., zero address) are added to local scope table.
+   */
+  if (application_has_local_scope (app)
+      && session_endpoint_is_local ((session_endpoint_t *) sep))
+    {
+      u32 table_index;
+
+      ll = application_local_listen_session_alloc (app);
+      ll->port = sep->port;
+      /* Store the original session type for the unbind */
+      ll->listener_session_type = st;
+      table_index = application_local_session_table (app);
+      lh = application_local_session_handle (ll);
+      session_lookup_add_session_endpoint (table_index,
+					   (session_endpoint_t *) sep, lh);
+      app_listener->local_index = ll->session_index;
+      ll->al_index = app_listener->al_index;
+    }
+
+  if (application_has_global_scope (app))
+    {
+      /*
+       * Start listening on local endpoint for requested transport and scope.
+       * Creates a stream session with state LISTENING to be used in session
+       * lookups, prior to establishing connection. Requests transport to
+       * build it's own specific listening connection.
+       */
+      ls = listen_session_new (0, st);
+      ls->app_index = app->app_index;
+      ls->app_wrk_index = sep->app_wrk_index;
+
+      /* Listen pool can be reallocated if the transport is
+       * recursive (tls) */
+      lh = session_handle (ls);
+
+      if ((rv = session_listen (ls, sep)))
+	{
+	  ls = session_get_from_handle (lh);
+	  session_free (ls);
+	  return rv;
+	}
+      app_listener->session_index = ls->session_index;
+      ls->al_index = app_listener->al_index;
+    }
+
+  if (!ll && !ls)
+    {
+      app_listener_free (app, app_listener);
+      return -1;
+    }
+
+  *listener = app_listener;
+  return 0;
 }
 
-static app_listener_t *
-app_local_listener_get (application_t * app, u32 app_listener_index)
+void
+app_listener_cleanup (app_listener_t * al)
+{
+  application_t *app = application_get (al->app_index);
+
+  if (al->session_index != SESSION_INVALID_INDEX)
+    {
+      session_t *ls = session_get (al->session_index, 0);
+      session_stop_listen (ls);
+      listen_session_del (ls);
+    }
+  if (al->local_index != SESSION_INVALID_INDEX)
+    {
+      session_endpoint_t sep = SESSION_ENDPOINT_NULL;
+      local_session_t *ll;
+      u32 table_index;
+
+      table_index = application_local_session_table (app);
+      ll = application_get_local_listen_session (app, al->local_index);
+      application_local_listener_session_endpoint (ll, &sep);
+      session_lookup_del_session_endpoint (table_index, &sep);
+      application_local_listen_session_free (app, ll);
+    }
+  app_listener_free (app, al);
+}
+
+app_worker_t *
+app_listener_select_worker (app_listener_t * al)
 {
-  return pool_elt_at_index (app->local_listeners, app_listener_index);
+  application_t *app;
+  u32 wrk_index;
+
+  app = application_get (al->app_index);
+  wrk_index = clib_bitmap_next_set (al->workers, al->accept_rotor + 1);
+  if (wrk_index == ~0)
+    wrk_index = clib_bitmap_first_set (al->workers);
+
+  ASSERT (wrk_index != ~0);
+  al->accept_rotor = wrk_index;
+  return application_get_worker (app, wrk_index);
 }
 
-static void
-app_local_listener_free (application_t * app, app_listener_t * app_listener)
+session_t *
+app_listener_get_session (app_listener_t * al)
 {
-  clib_bitmap_free (app_listener->workers);
-  pool_put (app->local_listeners, app_listener);
-  if (CLIB_DEBUG)
-    clib_memset (app_listener, 0xfa, sizeof (*app_listener));
+  if (al->session_index == SESSION_INVALID_INDEX)
+    return 0;
+
+  return listen_session_get (al->session_index);
 }
 
 static app_worker_map_t *
@@ -130,16 +356,6 @@ application_local_session_table (application_t * app)
   return app_ns->local_table_index;
 }
 
-static void
-application_local_listener_session_endpoint (local_session_t * ll,
-					     session_endpoint_t * sep)
-{
-  sep->transport_proto =
-    session_type_transport_proto (ll->listener_session_type);
-  sep->port = ll->port;
-  sep->is_ip4 = ll->listener_session_type & 1;
-}
-
 /**
  * Returns app name for app-index
  */
@@ -475,26 +691,12 @@ application_n_workers (application_t * app)
 }
 
 app_worker_t *
-application_listener_select_worker (session_t * ls, u8 is_local)
+application_listener_select_worker (session_t * ls)
 {
-  app_listener_t *app_listener;
-  application_t *app;
-  u32 wrk_index;
+  app_listener_t *al;
 
-  app = application_get (ls->app_index);
-  if (!is_local)
-    app_listener = app_listener_get (app, ls->listener_db_index);
-  else
-    app_listener = app_local_listener_get (app, ls->listener_db_index);
-
-  wrk_index = clib_bitmap_next_set (app_listener->workers,
-				    app_listener->accept_rotor + 1);
-  if (wrk_index == ~0)
-    wrk_index = clib_bitmap_first_set (app_listener->workers);
-
-  ASSERT (wrk_index != ~0);
-  app_listener->accept_rotor = wrk_index;
-  return application_get_worker (app, wrk_index);
+  al = app_listener_get_w_session (ls);
+  return app_listener_select_worker (al);
 }
 
 int
@@ -545,88 +747,6 @@ application_alloc_worker_and_init (application_t * app, app_worker_t ** wrk)
   return 0;
 }
 
-/**
- * Start listening local transport endpoint for requested transport.
- *
- * Creates a 'dummy' stream session with state LISTENING to be used in session
- * lookups, prior to establishing connection. Requests transport to build
- * it's own specific listening connection.
- */
-int
-application_start_listen (application_t * app,
-			  session_endpoint_cfg_t * sep_ext,
-			  session_handle_t * res)
-{
-  app_listener_t *app_listener;
-  u32 table_index, fib_proto;
-  session_endpoint_t *sep;
-  app_worker_t *app_wrk;
-  session_t *ls;
-  session_handle_t lh;
-  session_type_t sst;
-
-  /*
-   * Check if sep is already listened on
-   */
-  sep = (session_endpoint_t *) sep_ext;
-  fib_proto = session_endpoint_fib_proto (sep);
-  table_index = application_session_table (app, fib_proto);
-  lh = session_lookup_endpoint_listener (table_index, sep, 1);
-  if (lh != SESSION_INVALID_HANDLE)
-    {
-      ls = listen_session_get_from_handle (lh);
-      if (ls->app_index != app->app_index)
-	return VNET_API_ERROR_ADDRESS_IN_USE;
-
-      app_wrk = app_worker_get (sep_ext->app_wrk_index);
-      if (ls->app_wrk_index == app_wrk->wrk_index)
-	return VNET_API_ERROR_ADDRESS_IN_USE;
-
-      if (app_worker_start_listen (app_wrk, ls))
-	return -1;
-
-      app_listener = app_listener_get (app, ls->listener_db_index);
-      app_listener->workers = clib_bitmap_set (app_listener->workers,
-					       app_wrk->wrk_map_index, 1);
-
-      *res = listen_session_get_handle (ls);
-      return 0;
-    }
-
-  /*
-   * Allocate new listener for application
-   */
-  sst = session_type_from_proto_and_ip (sep_ext->transport_proto,
-					sep_ext->is_ip4);
-  ls = listen_session_new (0, sst);
-  ls->app_index = app->app_index;
-  lh = listen_session_get_handle (ls);
-  if (session_listen (ls, sep_ext))
-    goto err;
-
-
-  ls = listen_session_get_from_handle (lh);
-  app_listener = app_listener_alloc (app);
-  ls->listener_db_index = app_listener->al_index;
-
-  /*
-   * Setup app worker as a listener
-   */
-  app_wrk = app_worker_get (sep_ext->app_wrk_index);
-  ls->app_wrk_index = app_wrk->wrk_index;
-  if (app_worker_start_listen (app_wrk, ls))
-    goto err;
-  app_listener->workers = clib_bitmap_set (app_listener->workers,
-					   app_wrk->wrk_map_index, 1);
-
-  *res = lh;
-  return 0;
-
-err:
-  listen_session_del (ls);
-  return -1;
-}
-
 int
 application_change_listener_owner (session_t * s, app_worker_t * app_wrk)
 {
@@ -643,65 +763,20 @@ application_change_listener_owner (session_t * s, app_worker_t * app_wrk)
     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 = app_listener_get (app, s->al_index);
+
+  /* Only remove from lb for now */
   app_listener->workers = clib_bitmap_set (app_listener->workers,
 					   old_wrk->wrk_map_index, 0);
-  return 0;
-}
-
-/**
- * Stop listening on session associated to handle
- *
- * @param handle	listener handle
- * @param app_index	index of the app owning the handle.
- * @param app_wrk_index	index of the worker requesting the stop
- */
-int
-application_stop_listen (u32 app_index, u32 app_wrk_index,
-			 session_handle_t handle)
-{
-  app_listener_t *app_listener;
-  session_t *listener;
-  app_worker_t *app_wrk;
-  application_t *app;
-
-  listener = listen_session_get_from_handle (handle);
-  app = application_get (app_index);
-  if (PREDICT_FALSE (!app || app->app_index != listener->app_index))
-    {
-      clib_warning ("app doesn't own handle %llu!", handle);
-      return -1;
-    }
 
-  app_listener = app_listener_get (app, listener->listener_db_index);
-  if (!clib_bitmap_get (app_listener->workers, app_wrk_index))
-    {
-      clib_warning ("worker %u not listening on handle %lu", app_wrk_index,
-		    handle);
-      return 0;
-    }
-
-  app_wrk = application_get_worker (app, app_wrk_index);
-  app_worker_stop_listen (app_wrk, handle);
-  clib_bitmap_set_no_check (app_listener->workers, app_wrk_index, 0);
+  if (app_worker_start_listen (app_wrk, app_listener))
+    return -1;
 
-  if (clib_bitmap_is_zero (app_listener->workers))
-    {
-      session_stop_listen (listener);
-      app_listener_free (app, app_listener);
-      listen_session_del (listener);
-    }
+  s->app_wrk_index = app_wrk->wrk_index;
 
   return 0;
 }
@@ -803,8 +878,9 @@ application_start_stop_proxy_fib_proto (application_t * app, u8 fib_proto,
   session_endpoint_cfg_t sep = SESSION_ENDPOINT_CFG_NULL;
   transport_connection_t *tc;
   app_worker_t *app_wrk;
+  app_listener_t *al;
   session_t *s;
-  u64 handle;
+  u32 flags;
 
   /* TODO decide if we want proxy to be enabled for all workers */
   app_wrk = application_get_default_worker (app);
@@ -818,8 +894,15 @@ application_start_stop_proxy_fib_proto (application_t * app, u8 fib_proto,
 	  sep.sw_if_index = app_ns->sw_if_index;
 	  sep.transport_proto = transport_proto;
 	  sep.app_wrk_index = app_wrk->wrk_index;	/* only default */
-	  application_start_listen (app, &sep, &handle);
-	  s = listen_session_get_from_handle (handle);
+
+	  /* force global scope listener */
+	  flags = app->flags;
+	  app->flags &= ~APP_OPTIONS_FLAGS_USE_LOCAL_SCOPE;
+	  app_listener_alloc_and_init (app, &sep, &al);
+	  app->flags = flags;
+
+	  app_worker_start_listen (app_wrk, al);
+	  s = listen_session_get (al->session_index);
 	  s->enqueue_epoch = SESSION_PROXY_LISTENER_INDEX;
 	}
     }
@@ -939,165 +1022,6 @@ application_get_segment_manager_properties (u32 app_index)
   return &app->sm_properties;
 }
 
-local_session_t *
-application_local_listen_session_alloc (application_t * app)
-{
-  local_session_t *ll;
-  pool_get (app->local_listen_sessions, ll);
-  clib_memset (ll, 0, sizeof (*ll));
-  return ll;
-}
-
-u32
-application_local_listener_index (application_t * app, local_session_t * ll)
-{
-  return (ll - app->local_listen_sessions);
-}
-
-void
-application_local_listen_session_free (application_t * app,
-				       local_session_t * ll)
-{
-  pool_put (app->local_listen_sessions, ll);
-  if (CLIB_DEBUG)
-    clib_memset (ll, 0xfb, sizeof (*ll));
-}
-
-int
-application_start_local_listen (application_t * app,
-				session_endpoint_cfg_t * sep_ext,
-				session_handle_t * handle)
-{
-  app_listener_t *app_listener;
-  session_endpoint_t *sep;
-  app_worker_t *app_wrk;
-  session_handle_t lh;
-  local_session_t *ll;
-  u32 table_index;
-
-  sep = (session_endpoint_t *) sep_ext;
-  table_index = application_local_session_table (app);
-  app_wrk = app_worker_get (sep_ext->app_wrk_index);
-
-  /* An exact sep match, as opposed to session_lookup_local_listener */
-  lh = session_lookup_endpoint_listener (table_index, sep, 1);
-  if (lh != SESSION_INVALID_HANDLE)
-    {
-      ll = application_get_local_listener_w_handle (lh);
-      if (ll->app_index != app->app_index)
-	return VNET_API_ERROR_ADDRESS_IN_USE;
-
-      if (ll->app_wrk_index == app_wrk->wrk_index)
-	return VNET_API_ERROR_ADDRESS_IN_USE;
-
-      app_listener = app_local_listener_get (app, ll->listener_db_index);
-      app_listener->workers = clib_bitmap_set (app_listener->workers,
-					       app_wrk->wrk_map_index, 1);
-      *handle = application_local_session_handle (ll);
-      return 0;
-    }
-
-  ll = application_local_listen_session_alloc (app);
-  ll->session_type = session_type_from_proto_and_ip (TRANSPORT_PROTO_NONE, 0);
-  ll->app_wrk_index = app_wrk->app_index;
-  ll->session_index = application_local_listener_index (app, ll);
-  ll->port = sep_ext->port;
-  /* Store the original session type for the unbind */
-  ll->listener_session_type =
-    session_type_from_proto_and_ip (sep_ext->transport_proto,
-				    sep_ext->is_ip4);
-  ll->transport_listener_index = ~0;
-  ll->app_index = app->app_index;
-
-  app_listener = app_local_listener_alloc (app);
-  ll->listener_db_index = app_listener->al_index;
-  app_listener->workers = clib_bitmap_set (app_listener->workers,
-					   app_wrk->wrk_map_index, 1);
-
-  *handle = application_local_session_handle (ll);
-  session_lookup_add_session_endpoint (table_index, sep, *handle);
-
-  return 0;
-}
-
-/**
- * Clean up local session table. If we have a listener session use it to
- * find the port and proto. If not, the handle must be a local table handle
- * so parse it.
- */
-int
-application_stop_local_listen (u32 app_index, u32 wrk_map_index,
-			       session_handle_t lh)
-{
-  session_endpoint_t sep = SESSION_ENDPOINT_NULL;
-  u32 table_index, ll_index, server_index;
-  app_listener_t *app_listener;
-  app_worker_t *server_wrk;
-  session_t *sl = 0;
-  local_session_t *ll, *ls;
-  application_t *server;
-
-  server = application_get (app_index);
-  table_index = application_local_session_table (server);
-
-  /* We have both local and global table binds. Figure from global what
-   * sep we should be cleaning up.
-   */
-  if (!session_handle_is_local (lh))
-    {
-      sl = listen_session_get_from_handle (lh);
-      if (!sl || listen_session_get_local_session_endpoint (sl, &sep))
-	{
-	  clib_warning ("broken listener");
-	  return -1;
-	}
-      lh = session_lookup_endpoint_listener (table_index, &sep, 0);
-      if (lh == SESSION_INVALID_HANDLE)
-	return -1;
-    }
-
-  local_session_parse_handle (lh, &server_index, &ll_index);
-  if (PREDICT_FALSE (server_index != app_index))
-    {
-      clib_warning ("app %u does not own local handle 0x%lx", app_index, lh);
-      return -1;
-    }
-
-  ll = application_get_local_listen_session (server, ll_index);
-  if (PREDICT_FALSE (!ll))
-    {
-      clib_warning ("no local listener");
-      return -1;
-    }
-
-  app_listener = app_local_listener_get (server, ll->listener_db_index);
-  if (!clib_bitmap_get (app_listener->workers, wrk_map_index))
-    {
-      clib_warning ("app wrk %u not listening on handle %lu", wrk_map_index,
-		    lh);
-      return -1;
-    }
-
-  server_wrk = application_get_worker (server, wrk_map_index);
-  /* *INDENT-OFF* */
-  pool_foreach (ls, server_wrk->local_sessions, ({
-    if (ls->listener_index == ll->session_index)
-      app_worker_local_session_disconnect (server_wrk->app_index, ls);
-  }));
-  /* *INDENT-ON* */
-
-  clib_bitmap_set_no_check (app_listener->workers, wrk_map_index, 0);
-  if (clib_bitmap_is_zero (app_listener->workers))
-    {
-      app_local_listener_free (server, app_listener);
-      application_local_listener_session_endpoint (ll, &sep);
-      session_lookup_del_session_endpoint (table_index, &sep);
-      application_local_listen_session_free (server, ll);
-    }
-
-  return 0;
-}
-
 clib_error_t *
 vnet_app_add_tls_cert (vnet_app_add_tls_cert_args_t * a)
 {
diff --git a/src/vnet/session/application.h b/src/vnet/session/application.h
index e5bb00e2b14..d641263497c 100644
--- a/src/vnet/session/application.h
+++ b/src/vnet/session/application.h
@@ -116,6 +116,9 @@ typedef struct app_listener_
   clib_bitmap_t *workers;	/**< workers accepting connections */
   u32 accept_rotor;		/**< last worker to accept a connection */
   u32 al_index;
+  u32 app_index;
+  u32 local_index;
+  u32 session_index;
 } app_listener_t;
 
 typedef struct application_
@@ -215,6 +218,19 @@ typedef struct _vnet_app_worker_add_del_args
 #define APP_NS_INVALID_INDEX ((u32)~0)
 #define APP_INVALID_SEGMENT_MANAGER_INDEX ((u32) ~0)
 
+app_listener_t *app_listener_get (application_t * app, u32 al_index);
+int app_listener_alloc_and_init (application_t * app,
+				 session_endpoint_cfg_t * sep,
+				 app_listener_t ** listener);
+void app_listener_cleanup (app_listener_t * app_listener);
+session_handle_t app_listener_handle (app_listener_t * app_listener);
+app_listener_t *app_listener_lookup (application_t * app,
+				     session_endpoint_cfg_t * sep);
+app_listener_t *app_listener_get_w_handle (session_handle_t handle);
+app_listener_t *app_listener_get_w_session (session_t * ls);
+app_worker_t *app_listener_select_worker (app_listener_t * al);
+session_t *app_listener_get_session (app_listener_t * al);
+
 application_t *application_alloc (void);
 int application_alloc_and_init (app_init_args_t * args);
 void application_free (application_t * app);
@@ -225,13 +241,7 @@ application_t *application_lookup (u32 api_client_index);
 application_t *application_lookup_name (const u8 * name);
 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);
+app_worker_t *application_listener_select_worker (session_t * ls);
 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);
@@ -263,10 +273,10 @@ 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);
+int app_worker_connect_session (app_worker_t * app, session_endpoint_t * tep,
+				u32 api_context);
+int app_worker_start_listen (app_worker_t * app_wrk, app_listener_t * lstnr);
+int app_worker_stop_listen (app_worker_t * app_wrk, app_listener_t * al);
 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 *);
@@ -298,13 +308,6 @@ 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,
-				    session_endpoint_cfg_t * sep,
-				    session_handle_t * handle);
-int application_stop_local_listen (u32 app_index, u32 app_or_wrk,
-				   session_handle_t lh);
 int app_worker_local_session_connect (app_worker_t * client,
 				      app_worker_t * server,
 				      local_session_t * ls, u32 opaque);
diff --git a/src/vnet/session/application_interface.c b/src/vnet/session/application_interface.c
index c00c4ded1c7..11dc97d89b7 100644
--- a/src/vnet/session/application_interface.c
+++ b/src/vnet/session/application_interface.c
@@ -13,7 +13,6 @@
  * limitations under the License.
  */
 #include <vnet/session/application_interface.h>
-
 #include <vnet/session/session.h>
 #include <vlibmemory/api.h>
 #include <vnet/dpo/load_balance.h>
@@ -88,19 +87,6 @@ const u32 test_srv_key_rsa_len = sizeof (test_srv_key_rsa);
       return 0;								\
     }
 
-static u8
-session_endpoint_is_local (session_endpoint_t * sep)
-{
-  return (ip_is_zero (&sep->ip, sep->is_ip4)
-	  || ip_is_local_host (&sep->ip, sep->is_ip4));
-}
-
-static u8
-session_endpoint_is_zero (session_endpoint_t * sep)
-{
-  return ip_is_zero (&sep->ip, sep->is_ip4);
-}
-
 u8
 session_endpoint_in_ns (session_endpoint_t * sep)
 {
@@ -188,20 +174,21 @@ session_endpoint_update_for_app (session_endpoint_cfg_t * sep,
 }
 
 static inline int
-vnet_bind_inline (vnet_bind_args_t * a)
+vnet_listen_inline (vnet_listen_args_t * a)
 {
-  u64 ll_handle = SESSION_INVALID_HANDLE;
+  app_listener_t *app_listener;
   app_worker_t *app_wrk;
   application_t *app;
   int rv;
 
   app = application_get_if_valid (a->app_index);
   if (!app)
-    {
-      SESSION_DBG ("app not attached");
-      return VNET_API_ERROR_APPLICATION_NOT_ATTACHED;
-    }
+    return VNET_API_ERROR_APPLICATION_NOT_ATTACHED;
+
   app_wrk = application_get_worker (app, a->wrk_map_index);
+  if (!app_wrk)
+    return VNET_API_ERROR_INVALID_VALUE;
+
   a->sep_ext.app_wrk_index = app_wrk->wrk_index;
 
   session_endpoint_update_for_app (&a->sep_ext, app, 0 /* is_connect */ );
@@ -209,87 +196,71 @@ vnet_bind_inline (vnet_bind_args_t * a)
     return VNET_API_ERROR_INVALID_VALUE_2;
 
   /*
-   * Add session endpoint to local session table. Only binds to "inaddr_any"
-   * (i.e., zero address) are added to local scope table.
+   * Check if we already have an app listener
    */
-  if (application_has_local_scope (app)
-      && session_endpoint_is_local (&a->sep))
+  app_listener = app_listener_lookup (app, &a->sep_ext);
+  if (app_listener)
     {
-      if ((rv = application_start_local_listen (app, &a->sep_ext,
-						&a->handle)))
-	return rv;
-      ll_handle = a->handle;
+      if (app_listener->app_index != app->app_index)
+	return VNET_API_ERROR_ADDRESS_IN_USE;
+      if (app_worker_start_listen (app_wrk, app_listener))
+	return -1;
+      a->handle = app_listener_handle (app_listener);
+      return 0;
     }
 
-  if (!application_has_global_scope (app))
-    return (ll_handle == SESSION_INVALID_HANDLE ? -1 : 0);
-
   /*
-   * Add session endpoint to global session table
+   * Create new app listener
    */
+  if ((rv = app_listener_alloc_and_init (app, &a->sep_ext, &app_listener)))
+    return rv;
 
-  /* Setup listen path down to transport */
-  rv = application_start_listen (app, &a->sep_ext, &a->handle);
-  if (rv && ll_handle != SESSION_INVALID_HANDLE)
+  if ((rv = app_worker_start_listen (app_wrk, app_listener)))
     {
-      application_stop_local_listen (a->app_index, a->wrk_map_index,
-				     ll_handle);
+      app_listener_cleanup (app_listener);
       return rv;
     }
 
-  /*
-   * Store in local table listener the index of the transport layer
-   * listener. We'll need if if local listeners are hit and we need to
-   * return global handle
-   */
-  if (ll_handle != SESSION_INVALID_HANDLE)
-    {
-      local_session_t *ll;
-      session_t *tl;
-      ll = application_get_local_listener_w_handle (ll_handle);
-      tl = listen_session_get_from_handle (a->handle);
-      if (ll->transport_listener_index == ~0)
-	ll->transport_listener_index = tl->session_index;
-    }
-  return rv;
+  a->handle = app_listener_handle (app_listener);
+  return 0;
 }
 
 static inline int
-vnet_unbind_inline (vnet_unbind_args_t * a)
+vnet_unlisten_inline (vnet_unbind_args_t * a)
 {
+  app_worker_t *app_wrk;
+  app_listener_t *al;
   application_t *app;
-  int rv;
 
   if (!(app = application_get_if_valid (a->app_index)))
+    return VNET_API_ERROR_APPLICATION_NOT_ATTACHED;
+
+  al = app_listener_get_w_handle (a->handle);
+  if (al->app_index != app->app_index)
     {
-      SESSION_DBG ("app (%d) not attached", wrk_map_index);
-      return VNET_API_ERROR_APPLICATION_NOT_ATTACHED;
+      clib_warning ("app doesn't own handle %llu!", a->handle);
+      return -1;
     }
 
-  if (application_has_local_scope (app))
+  app_wrk = application_get_worker (app, a->wrk_map_index);
+  if (!app_wrk)
     {
-      if ((rv = application_stop_local_listen (a->app_index,
-					       a->wrk_map_index, a->handle)))
-	return rv;
+      clib_warning ("no app %u worker %u", app->app_index, a->wrk_map_index);
+      return -1;
     }
 
-  /*
-   * Clear the global scope table of the listener
-   */
-  if (application_has_global_scope (app))
-    return application_stop_listen (a->app_index, a->wrk_map_index,
-				    a->handle);
-  return 0;
+  return app_worker_stop_listen (app_wrk, al);
 }
 
 static int
 application_connect (vnet_connect_args_t * a)
 {
   app_worker_t *server_wrk, *client_wrk;
-  u32 table_index, server_index, li;
-  session_t *listener;
-  application_t *client, *server;
+  application_t *client;
   local_session_t *ll;
+  app_listener_t *al;
+  u32 table_index;
+  session_t *ls;
   u8 fib_proto;
   u64 lh;
 
@@ -315,24 +286,20 @@ application_connect (vnet_connect_args_t * a)
       if (lh == SESSION_INVALID_HANDLE)
 	goto global_scope;
 
-      local_session_parse_handle (lh, &server_index, &li);
+      ll = application_get_local_listener_w_handle (lh);
+      al = app_listener_get_w_session ((session_t *) ll);
 
       /*
        * Break loop if rule in local table points to connecting app. This
        * can happen if client is a generic proxy. Route connect through
        * global table instead.
        */
-      if (server_index != a->app_index)
-	{
-	  server = application_get (server_index);
-	  ll = application_get_local_listen_session (server, li);
-	  listener = (session_t *) ll;
-	  server_wrk = application_listener_select_worker (listener,
-							   1 /* is_local */ );
-	  return app_worker_local_session_connect (client_wrk,
-						   server_wrk, ll,
-						   a->api_context);
-	}
+      if (al->app_index == a->app_index)
+	goto global_scope;
+
+      server_wrk = app_listener_select_worker (al);
+      return app_worker_local_session_connect (client_wrk, server_wrk, ll,
+					       a->api_context);
     }
 
   /*
@@ -349,12 +316,12 @@ global_scope:
 
   fib_proto = session_endpoint_fib_proto (&a->sep);
   table_index = application_session_table (client, fib_proto);
-  listener = session_lookup_listener (table_index, &a->sep);
-  if (listener)
+  ls = session_lookup_listener (table_index, &a->sep);
+  if (ls)
     {
-      server_wrk = application_listener_select_worker (listener,
-						       0 /* is_local */ );
-      ll = (local_session_t *) listener;
+      al = app_listener_get_w_session (ls);
+      server_wrk = app_listener_select_worker (al);
+      ll = (local_session_t *) ls;
       return app_worker_local_session_connect (client_wrk, server_wrk, ll,
 					       a->api_context);
     }
@@ -362,7 +329,7 @@ global_scope:
   /*
    * Not connecting to a local server, propagate to transport
    */
-  if (app_worker_open_session (client_wrk, &a->sep, a->api_context))
+  if (app_worker_connect_session (client_wrk, &a->sep, a->api_context))
     return VNET_API_ERROR_SESSION_CONNECT;
   return 0;
 }
@@ -586,7 +553,7 @@ vnet_application_detach (vnet_app_detach_args_t * a)
 }
 
 int
-vnet_bind_uri (vnet_bind_args_t * a)
+vnet_bind_uri (vnet_listen_args_t * a)
 {
   session_endpoint_cfg_t sep = SESSION_ENDPOINT_CFG_NULL;
   int rv;
@@ -596,7 +563,7 @@ vnet_bind_uri (vnet_bind_args_t * a)
     return rv;
   sep.app_wrk_index = 0;
   clib_memcpy (&a->sep_ext, &sep, sizeof (sep));
-  return vnet_bind_inline (a);
+  return vnet_listen_inline (a);
 }
 
 int
@@ -619,7 +586,7 @@ vnet_unbind_uri (vnet_unbind_args_t * a)
   if (!listener)
     return VNET_API_ERROR_ADDRESS_NOT_IN_USE;
   a->handle = listen_session_get_handle (listener);
-  return vnet_unbind_inline (a);
+  return vnet_unlisten_inline (a);
 }
 
 clib_error_t *
@@ -675,19 +642,19 @@ vnet_disconnect_session (vnet_disconnect_args_t * a)
 }
 
 clib_error_t *
-vnet_bind (vnet_bind_args_t * a)
+vnet_listen (vnet_listen_args_t * a)
 {
   int rv;
-  if ((rv = vnet_bind_inline (a)))
+  if ((rv = vnet_listen_inline (a)))
     return clib_error_return_code (0, rv, 0, "bind failed: %d", rv);
   return 0;
 }
 
 clib_error_t *
-vnet_unbind (vnet_unbind_args_t * a)
+vnet_unlisten (vnet_unbind_args_t * a)
 {
   int rv;
-  if ((rv = vnet_unbind_inline (a)))
+  if ((rv = vnet_unlisten_inline (a)))
     return clib_error_return_code (0, rv, 0, "unbind failed: %d", rv);
   return 0;
 }
diff --git a/src/vnet/session/application_interface.h b/src/vnet/session/application_interface.h
index 8ecb0050592..ac6895ea50b 100644
--- a/src/vnet/session/application_interface.h
+++ b/src/vnet/session/application_interface.h
@@ -16,7 +16,7 @@
 #define __included_uri_h__
 
 #include <svm/svm_fifo_segment.h>
-#include <vnet/session/session.h>
+#include <vnet/session/session_types.h>
 #include <vnet/session/application.h>
 #include <vnet/session/transport.h>
 #include <vnet/tls/tls.h>
@@ -56,7 +56,7 @@ typedef struct _vnet_bind_args_t
   u32 segment_name_length;
   u64 server_event_queue_address;
   u64 handle;
-} vnet_bind_args_t;
+} vnet_listen_args_t;
 
 typedef struct _vnet_unbind_args_t
 {
@@ -167,14 +167,14 @@ typedef enum session_fd_flag_
 #undef _
 } session_fd_flag_t;
 
-int vnet_bind_uri (vnet_bind_args_t *);
+int vnet_bind_uri (vnet_listen_args_t *);
 int vnet_unbind_uri (vnet_unbind_args_t * a);
 clib_error_t *vnet_connect_uri (vnet_connect_args_t * a);
 
 clib_error_t *vnet_application_attach (vnet_app_attach_args_t * a);
-clib_error_t *vnet_bind (vnet_bind_args_t * a);
+clib_error_t *vnet_listen (vnet_listen_args_t * a);
 clib_error_t *vnet_connect (vnet_connect_args_t * a);
-clib_error_t *vnet_unbind (vnet_unbind_args_t * a);
+clib_error_t *vnet_unlisten (vnet_unbind_args_t * a);
 int vnet_application_detach (vnet_app_detach_args_t * a);
 int vnet_disconnect_session (vnet_disconnect_args_t * a);
 
diff --git a/src/vnet/session/application_worker.c b/src/vnet/session/application_worker.c
index 89ee6057172..44e0d399433 100644
--- a/src/vnet/session/application_worker.c
+++ b/src/vnet/session/application_worker.c
@@ -164,15 +164,18 @@ app_worker_free (app_worker_t * app_wrk)
   segment_manager_t *sm;
   u32 sm_index;
   int i;
+  app_listener_t *al;
+  session_t *ls;
 
   /*
    *  Listener cleanup
    */
 
   /* *INDENT-OFF* */
-  hash_foreach (handle, sm_index, app_wrk->listeners_table,
-  ({
-    vec_add1 (handles, handle);
+  hash_foreach (handle, sm_index, app_wrk->listeners_table, ({
+    ls = listen_session_get_from_handle (handle);
+    al = app_listener_get (app, ls->al_index);
+    vec_add1 (handles, app_listener_handle (al));
     sm = segment_manager_get (sm_index);
     sm->app_wrk_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
   }));
@@ -184,7 +187,7 @@ app_worker_free (app_worker_t * app_wrk)
       a->wrk_map_index = app_wrk->wrk_map_index;
       a->handle = handles[i];
       /* seg manager is removed when unbind completes */
-      vnet_unbind (a);
+      vnet_unlisten (a);
     }
 
   /*
@@ -252,54 +255,97 @@ app_worker_alloc_segment_manager (app_worker_t * app_wrk)
 }
 
 int
-app_worker_start_listen (app_worker_t * app_wrk, session_t * ls)
+app_worker_start_listen (app_worker_t * app_wrk,
+			 app_listener_t * app_listener)
 {
   segment_manager_t *sm;
+  session_t *ls;
+
+  if (clib_bitmap_get (app_listener->workers, app_wrk->wrk_map_index))
+    return VNET_API_ERROR_ADDRESS_IN_USE;
+
+  app_listener->workers = clib_bitmap_set (app_listener->workers,
+					   app_wrk->wrk_map_index, 1);
+
+  if (app_listener->session_index == SESSION_INVALID_INDEX)
+    return 0;
+
+  ls = session_get (app_listener->session_index, 0);
 
   /* 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 */
+  /* Keep track of the segment manager for the listener or this worker */
   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_transport_service_type (ls) == TRANSPORT_SERVICE_CL)
     {
-      if (session_alloc_fifos (sm, ls))
+      if (!ls->rx_fifo && session_alloc_fifos (sm, ls))
 	return -1;
     }
   return 0;
 }
 
 int
-app_worker_stop_listen (app_worker_t * app_wrk, session_handle_t handle)
+app_worker_stop_listen (app_worker_t * app_wrk, app_listener_t * al)
 {
+  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;
-    }
+  if (!clib_bitmap_get (al->workers, app_wrk->wrk_map_index))
+    return 0;
 
-  sm = segment_manager_get (*sm_indexp);
-  if (app_wrk->first_segment_manager == *sm_indexp)
+  if (al->session_index != SESSION_INVALID_INDEX)
     {
-      /* Delete sessions but don't remove segment manager */
-      app_wrk->first_segment_manager_in_use = 0;
-      segment_manager_del_sessions (sm);
+      session_t *ls;
+
+      ls = listen_session_get (al->session_index);
+      handle = listen_session_get_handle (ls);
+
+      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);
     }
-  else
+
+  if (al->local_index != SESSION_INVALID_INDEX)
     {
-      segment_manager_init_del (sm);
+      local_session_t *ll, *ls;
+      application_t *app;
+
+      app = application_get (app_wrk->app_index);
+      ll = application_get_local_listen_session (app, al->local_index);
+
+      /* *INDENT-OFF* */
+      pool_foreach (ls, app_wrk->local_sessions, ({
+        if (ls->listener_index == ll->session_index)
+          app_worker_local_session_disconnect (app_wrk->app_index, ls);
+      }));
+      /* *INDENT-ON* */
     }
-  hash_unset (app_wrk->listeners_table, handle);
+
+  clib_bitmap_set_no_check (al->workers, app_wrk->wrk_map_index, 0);
+  if (clib_bitmap_is_zero (al->workers))
+    app_listener_cleanup (al);
 
   return 0;
 }
@@ -350,8 +396,8 @@ app_worker_own_session (app_worker_t * app_wrk, session_t * s)
 }
 
 int
-app_worker_open_session (app_worker_t * app, session_endpoint_t * sep,
-			 u32 api_context)
+app_worker_connect_session (app_worker_t * app, session_endpoint_t * sep,
+			    u32 api_context)
 {
   int rv;
 
@@ -405,7 +451,7 @@ app_worker_get_listen_segment_manager (app_worker_t * app,
 }
 
 session_t *
-app_worker_first_listener (app_worker_t * app, u8 fib_proto,
+app_worker_first_listener (app_worker_t * app_wrk, u8 fib_proto,
 			   u8 transport_proto)
 {
   session_t *listener;
@@ -417,7 +463,7 @@ app_worker_first_listener (app_worker_t * app, u8 fib_proto,
 					fib_proto == FIB_PROTOCOL_IP4);
 
   /* *INDENT-OFF* */
-   hash_foreach (handle, sm_index, app->listeners_table, ({
+   hash_foreach (handle, sm_index, app_wrk->listeners_table, ({
      listener = listen_session_get_from_handle (handle);
      if (listener->session_type == sst
 	 && listener->enqueue_epoch != SESSION_PROXY_LISTENER_INDEX)
@@ -429,7 +475,7 @@ app_worker_first_listener (app_worker_t * app, u8 fib_proto,
 }
 
 session_t *
-app_worker_proxy_listener (app_worker_t * app, u8 fib_proto,
+app_worker_proxy_listener (app_worker_t * app_wrk, u8 fib_proto,
 			   u8 transport_proto)
 {
   session_t *listener;
@@ -441,7 +487,7 @@ app_worker_proxy_listener (app_worker_t * app, u8 fib_proto,
 					fib_proto == FIB_PROTOCOL_IP4);
 
   /* *INDENT-OFF* */
-   hash_foreach (handle, sm_index, app->listeners_table, ({
+   hash_foreach (handle, sm_index, app_wrk->listeners_table, ({
      listener = listen_session_get_from_handle (handle);
      if (listener->session_type == sst
 	 && listener->enqueue_epoch == SESSION_PROXY_LISTENER_INDEX)
@@ -1040,6 +1086,7 @@ void
 app_worker_format_local_sessions (app_worker_t * app_wrk, int verbose)
 {
   vlib_main_t *vm = vlib_get_main ();
+  app_worker_t *client_wrk;
   local_session_t *ls;
   transport_proto_t tp;
   u8 *conn = 0;
@@ -1061,8 +1108,9 @@ app_worker_format_local_sessions (app_worker_t * app_wrk, int verbose)
     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);
+    client_wrk = app_worker_get (ls->client_wrk_index);
+    vlib_cli_output (vm, "%-40v%-15u%-20u", conn, ls->app_index,
+                     client_wrk->app_index);
     vec_reset_length (conn);
   }));
   /* *INDENT-ON* */
diff --git a/src/vnet/session/session.c b/src/vnet/session/session.c
index 6833a93e12b..532a242cc5f 100644
--- a/src/vnet/session/session.c
+++ b/src/vnet/session/session.c
@@ -945,7 +945,7 @@ session_transport_reset_notify (transport_connection_t * tc)
  * Accept a stream session. Optionally ping the server by callback.
  */
 int
-stream_session_accept (transport_connection_t * tc, u32 listener_index,
+session_stream_accept (transport_connection_t * tc, u32 listener_index,
 		       u8 notify)
 {
   session_t *s, *listener;
@@ -955,7 +955,7 @@ stream_session_accept (transport_connection_t * tc, u32 listener_index,
 
   /* Find the server */
   listener = listen_session_get (listener_index);
-  app_wrk = application_listener_select_worker (listener, 0);
+  app_wrk = application_listener_select_worker (listener);
 
   sm = app_worker_get_listen_segment_manager (app_wrk, listener);
   if ((rv = session_alloc_and_init (sm, tc, 1, &s)))
@@ -1119,7 +1119,7 @@ session_listen (session_t * ls, session_endpoint_cfg_t * sep)
 
   /* Add to the main lookup table after transport was initialized */
   tc = transport_get_listener (sep->transport_proto, tc_index);
-  session_lookup_add_connection (tc, s_index);
+  session_lookup_add_connection (tc, listen_session_get_handle (ls));
   return 0;
 }
 
diff --git a/src/vnet/session/session.h b/src/vnet/session/session.h
index c622e4eb74a..7722f4f03e3 100644
--- a/src/vnet/session/session.h
+++ b/src/vnet/session/session.h
@@ -23,58 +23,6 @@
 
 #define SESSION_PROXY_LISTENER_INDEX ((u8)~0 - 1)
 
-typedef enum
-{
-  FIFO_EVENT_APP_RX,
-  SESSION_IO_EVT_CT_RX,
-  FIFO_EVENT_APP_TX,
-  SESSION_IO_EVT_CT_TX,
-  SESSION_IO_EVT_TX_FLUSH,
-  FIFO_EVENT_DISCONNECT,
-  FIFO_EVENT_BUILTIN_RX,
-  FIFO_EVENT_BUILTIN_TX,
-  FIFO_EVENT_RPC,
-  SESSION_CTRL_EVT_BOUND,
-  SESSION_CTRL_EVT_ACCEPTED,
-  SESSION_CTRL_EVT_ACCEPTED_REPLY,
-  SESSION_CTRL_EVT_CONNECTED,
-  SESSION_CTRL_EVT_CONNECTED_REPLY,
-  SESSION_CTRL_EVT_DISCONNECTED,
-  SESSION_CTRL_EVT_DISCONNECTED_REPLY,
-  SESSION_CTRL_EVT_RESET,
-  SESSION_CTRL_EVT_RESET_REPLY,
-  SESSION_CTRL_EVT_REQ_WORKER_UPDATE,
-  SESSION_CTRL_EVT_WORKER_UPDATE,
-  SESSION_CTRL_EVT_WORKER_UPDATE_REPLY,
-} session_evt_type_t;
-
-static inline const char *
-fifo_event_type_str (session_evt_type_t et)
-{
-  switch (et)
-    {
-    case FIFO_EVENT_APP_RX:
-      return "FIFO_EVENT_APP_RX";
-    case FIFO_EVENT_APP_TX:
-      return "FIFO_EVENT_APP_TX";
-    case FIFO_EVENT_DISCONNECT:
-      return "FIFO_EVENT_DISCONNECT";
-    case FIFO_EVENT_BUILTIN_RX:
-      return "FIFO_EVENT_BUILTIN_RX";
-    case FIFO_EVENT_RPC:
-      return "FIFO_EVENT_RPC";
-    default:
-      return "UNKNOWN FIFO EVENT";
-    }
-}
-
-typedef enum
-{
-  SESSION_MQ_IO_EVT_RING,
-  SESSION_MQ_CTRL_EVT_RING,
-  SESSION_MQ_N_RINGS
-} session_mq_rings_e;
-
 #define foreach_session_input_error                                    	\
 _(NO_SESSION, "No session drops")                                       \
 _(NO_LISTENER, "No listener for dst port drops")                        \
@@ -95,57 +43,6 @@ typedef enum
     SESSION_N_ERROR,
 } session_error_t;
 
-typedef struct
-{
-  void *fp;
-  void *arg;
-} session_rpc_args_t;
-
-/* *INDENT-OFF* */
-typedef struct
-{
-  u8 event_type;
-  u8 postponed;
-  union
-  {
-    svm_fifo_t *fifo;
-    session_handle_t session_handle;
-    session_rpc_args_t rpc_args;
-    struct
-    {
-      u8 data[0];
-    };
-  };
-} __clib_packed session_event_t;
-/* *INDENT-ON* */
-
-#define SESSION_MSG_NULL { }
-
-typedef struct session_dgram_pre_hdr_
-{
-  u32 data_length;
-  u32 data_offset;
-} session_dgram_pre_hdr_t;
-
-/* *INDENT-OFF* */
-typedef CLIB_PACKED (struct session_dgram_header_
-{
-  u32 data_length;
-  u32 data_offset;
-  ip46_address_t rmt_ip;
-  ip46_address_t lcl_ip;
-  u16 rmt_port;
-  u16 lcl_port;
-  u8 is_ip4;
-}) session_dgram_hdr_t;
-/* *INDENT-ON* */
-
-#define SESSION_CONN_ID_LEN 37
-#define SESSION_CONN_HDR_LEN 45
-
-STATIC_ASSERT (sizeof (session_dgram_hdr_t) == (SESSION_CONN_ID_LEN + 8),
-	       "session conn id wrong length");
-
 typedef struct session_tx_context_
 {
   CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
@@ -493,7 +390,7 @@ void session_transport_closing_notify (transport_connection_t * tc);
 void session_transport_delete_notify (transport_connection_t * tc);
 void session_transport_closed_notify (transport_connection_t * tc);
 void session_transport_reset_notify (transport_connection_t * tc);
-int stream_session_accept (transport_connection_t * tc, u32 listener_index,
+int session_stream_accept (transport_connection_t * tc, u32 listener_index,
 			   u8 notify);
 u32 session_tx_fifo_max_dequeue (transport_connection_t * tc);
 void session_register_transport (transport_proto_t transport_proto,
diff --git a/src/vnet/session/session_api.c b/src/vnet/session/session_api.c
index 8196f4ca142..6a845519b83 100755
--- a/src/vnet/session/session_api.c
+++ b/src/vnet/session/session_api.c
@@ -19,6 +19,7 @@
 #include <vnet/session/application_interface.h>
 #include <vnet/session/session_rules_table.h>
 #include <vnet/session/session_table.h>
+#include <vnet/session/session.h>
 
 #include <vnet/vnet_msg_enum.h>
 
@@ -207,6 +208,7 @@ send_session_accept_callback (session_t * s)
   session_t *listener;
   svm_msg_q_t *vpp_queue;
   application_t *server;
+  app_listener_t *al;
 
   server = application_get (server_wrk->app_index);
   reg =
@@ -228,7 +230,8 @@ send_session_accept_callback (session_t * s)
   if (session_has_transport (s))
     {
       listener = listen_session_get (s->listener_index);
-      mp->listener_handle = listen_session_get_handle (listener);
+      al = app_listener_get (server, listener->al_index);
+      mp->listener_handle = app_listener_handle (al);
       if (application_is_proxy (server))
 	{
 	  listener =
@@ -253,22 +256,16 @@ send_session_accept_callback (session_t * s)
       if (application_local_session_listener_has_transport (ls))
 	{
 	  listener = listen_session_get (ls->listener_index);
-	  mp->listener_handle = listen_session_get_handle (listener);
+	  al = app_listener_get (server, listener->al_index);
+	  mp->listener_handle = app_listener_handle (al);
 	  mp->is_ip4 = session_type_is_ip4 (listener->session_type);
 	}
       else
 	{
 	  ll = application_get_local_listen_session (server,
 						     ls->listener_index);
-	  if (ll->transport_listener_index != ~0)
-	    {
-	      listener = listen_session_get (ll->transport_listener_index);
-	      mp->listener_handle = listen_session_get_handle (listener);
-	    }
-	  else
-	    {
-	      mp->listener_handle = application_local_session_handle (ll);
-	    }
+	  al = app_listener_get (server, ll->al_index);
+	  mp->listener_handle = app_listener_handle (al);
 	  mp->is_ip4 = session_type_is_ip4 (ll->listener_session_type);
 	}
       mp->handle = application_local_session_handle (ls);
@@ -424,6 +421,7 @@ mq_send_session_accepted_cb (session_t * s)
   session_accepted_msg_t *mp;
   session_event_t *evt;
   application_t *app;
+  app_listener_t *al;
 
   app = application_get (app_wrk->app_index);
   app_mq = app_wrk->event_queue;
@@ -443,7 +441,8 @@ mq_send_session_accepted_cb (session_t * s)
   if (session_has_transport (s))
     {
       listener = listen_session_get (s->listener_index);
-      mp->listener_handle = listen_session_get_handle (listener);
+      al = app_listener_get (app, listener->al_index);
+      mp->listener_handle = app_listener_handle (al);
       if (application_is_proxy (app))
 	{
 	  listener =
@@ -475,21 +474,15 @@ mq_send_session_accepted_cb (session_t * s)
       if (application_local_session_listener_has_transport (ls))
 	{
 	  listener = listen_session_get (ls->listener_index);
-	  mp->listener_handle = listen_session_get_handle (listener);
+	  al = app_listener_get (app, listener->al_index);
+	  mp->listener_handle = app_listener_handle (al);
 	  mp->is_ip4 = session_type_is_ip4 (listener->session_type);
 	}
       else
 	{
 	  ll = application_get_local_listen_session (app, ls->listener_index);
-	  if (ll->transport_listener_index != ~0)
-	    {
-	      listener = listen_session_get (ll->transport_listener_index);
-	      mp->listener_handle = listen_session_get_handle (listener);
-	    }
-	  else
-	    {
-	      mp->listener_handle = application_local_session_handle (ll);
-	    }
+	  al = app_listener_get (app, ll->al_index);
+	  mp->listener_handle = app_listener_handle (al);
 	  mp->is_ip4 = session_type_is_ip4 (ll->listener_session_type);
 	}
       mp->handle = application_local_session_handle (ls);
@@ -674,11 +667,12 @@ mq_send_session_bound_cb (u32 app_wrk_index, u32 api_context,
   svm_msg_q_msg_t _msg, *msg = &_msg;
   svm_msg_q_t *app_mq, *vpp_evt_q;
   transport_connection_t *tc;
-  session_t *ls = 0;
   session_bound_msg_t *mp;
   app_worker_t *app_wrk;
   session_event_t *evt;
   application_t *app;
+  app_listener_t *al;
+  session_t *ls = 0;
 
   app_wrk = app_worker_get (app_wrk_index);
   app = application_get (app_wrk->app_index);
@@ -705,7 +699,8 @@ mq_send_session_bound_cb (u32 app_wrk_index, u32 api_context,
   mp->handle = handle;
   if (application_has_global_scope (app))
     {
-      ls = listen_session_get_from_handle (handle);
+      al = app_listener_get_w_handle (handle);
+      ls = app_listener_get_session (al);
       tc = listen_session_get_transport (ls);
       mp->lcl_port = tc->lcl_port;
       mp->lcl_is_ip4 = tc->is_ip4;
@@ -888,7 +883,7 @@ static void
 vl_api_bind_uri_t_handler (vl_api_bind_uri_t * mp)
 {
   transport_connection_t *tc = 0;
-  vnet_bind_args_t _a, *a = &_a;
+  vnet_listen_args_t _a, *a = &_a;
   vl_api_bind_uri_reply_t *rmp;
   session_t *s;
   application_t *app = 0;
@@ -1180,16 +1175,17 @@ vl_api_map_another_segment_reply_t_handler (vl_api_map_another_segment_reply_t
 static void
 vl_api_bind_sock_t_handler (vl_api_bind_sock_t * mp)
 {
+  vnet_listen_args_t _a, *a = &_a;
+  transport_connection_t *tc = 0;
   vl_api_bind_sock_reply_t *rmp;
-  vnet_bind_args_t _a, *a = &_a;
-  int rv = 0;
-  clib_error_t *error;
+  svm_msg_q_t *vpp_evt_q;
   application_t *app = 0;
   app_worker_t *app_wrk;
-  session_t *s;
-  transport_connection_t *tc = 0;
   ip46_address_t *ip46;
-  svm_msg_q_t *vpp_evt_q;
+  clib_error_t *error;
+  app_listener_t *al;
+  session_t *s;
+  int rv = 0;
 
   if (session_manager_is_enabled () == 0)
     {
@@ -1215,7 +1211,7 @@ vl_api_bind_sock_t_handler (vl_api_bind_sock_t * mp)
   a->app_index = app->app_index;
   a->wrk_map_index = mp->wrk_index;
 
-  if ((error = vnet_bind (a)))
+  if ((error = vnet_listen (a)))
     {
       rv = clib_error_get_code (error);
       clib_error_report (error);
@@ -1231,7 +1227,8 @@ done:
 	rmp->lcl_is_ip4 = mp->is_ip4;
 	if (app && application_has_global_scope (app))
 	  {
-	    s = listen_session_get_from_handle (a->handle);
+	    al = app_listener_get_w_handle (a->handle);
+	    s = app_listener_get_session (al);
 	    tc = listen_session_get_transport (s);
             clib_memcpy_fast (rmp->lcl_ip, &tc->lcl_ip, sizeof (tc->lcl_ip));
             if (session_transport_service_type (s) == TRANSPORT_SERVICE_CL)
@@ -1276,7 +1273,7 @@ vl_api_unbind_sock_t_handler (vl_api_unbind_sock_t * mp)
       a->app_index = app->app_index;
       a->handle = mp->handle;
       a->wrk_map_index = mp->wrk_index;
-      if ((error = vnet_unbind (a)))
+      if ((error = vnet_unlisten (a)))
 	{
 	  rv = clib_error_get_code (error);
 	  clib_error_report (error);
diff --git a/src/vnet/session/session_types.h b/src/vnet/session/session_types.h
index 286f4c49d80..846af25c777 100644
--- a/src/vnet/session/session_types.h
+++ b/src/vnet/session/session_types.h
@@ -19,7 +19,8 @@
 #include <svm/svm_fifo.h>
 #include <vnet/session/transport_types.h>
 
-#define SESSION_LOCAL_HANDLE_PREFIX 0x7FFFFFFF
+#define SESSION_LOCAL_HANDLE_PREFIX 	0x7FFFFFFF
+#define SESSION_LISTENER_PREFIX		0x5FFFFFFF
 
 #define foreach_session_endpoint_fields				\
   foreach_transport_endpoint_cfg_fields				\
@@ -91,6 +92,19 @@ session_endpoint_fib_proto (session_endpoint_t * sep)
   return sep->is_ip4 ? FIB_PROTOCOL_IP4 : FIB_PROTOCOL_IP6;
 }
 
+static inline u8
+session_endpoint_is_local (session_endpoint_t * sep)
+{
+  return (ip_is_zero (&sep->ip, sep->is_ip4)
+	  || ip_is_local_host (&sep->ip, sep->is_ip4));
+}
+
+static inline u8
+session_endpoint_is_zero (session_endpoint_t * sep)
+{
+  return ip_is_zero (&sep->ip, sep->is_ip4);
+}
+
 typedef u8 session_type_t;
 typedef u64 session_handle_t;
 
@@ -164,8 +178,8 @@ typedef struct session_
     /** Transport app index for apps acting as transports */
     u32 t_app_index;
 
-    /** Index in listener app's listener db */
-    u32 listener_db_index;
+    /** App listener index */
+    u32 al_index;
 
     /** Opaque, for general use */
     u32 opaque;
@@ -303,7 +317,7 @@ typedef struct local_session_
     u32 app_index;
   };
 
-  u32 listener_db_index;
+  u32 al_index;
 
   /** Has transport embedded when listener not purely local */
   session_type_t listener_session_type;
@@ -364,6 +378,108 @@ application_local_session_handle (local_session_t * ls)
     | (u64) local_session_id (ls);
 }
 
+typedef enum
+{
+  FIFO_EVENT_APP_RX,
+  SESSION_IO_EVT_CT_RX,
+  FIFO_EVENT_APP_TX,
+  SESSION_IO_EVT_CT_TX,
+  SESSION_IO_EVT_TX_FLUSH,
+  FIFO_EVENT_DISCONNECT,
+  FIFO_EVENT_BUILTIN_RX,
+  FIFO_EVENT_BUILTIN_TX,
+  FIFO_EVENT_RPC,
+  SESSION_CTRL_EVT_BOUND,
+  SESSION_CTRL_EVT_ACCEPTED,
+  SESSION_CTRL_EVT_ACCEPTED_REPLY,
+  SESSION_CTRL_EVT_CONNECTED,
+  SESSION_CTRL_EVT_CONNECTED_REPLY,
+  SESSION_CTRL_EVT_DISCONNECTED,
+  SESSION_CTRL_EVT_DISCONNECTED_REPLY,
+  SESSION_CTRL_EVT_RESET,
+  SESSION_CTRL_EVT_RESET_REPLY,
+  SESSION_CTRL_EVT_REQ_WORKER_UPDATE,
+  SESSION_CTRL_EVT_WORKER_UPDATE,
+  SESSION_CTRL_EVT_WORKER_UPDATE_REPLY,
+} session_evt_type_t;
+
+static inline const char *
+fifo_event_type_str (session_evt_type_t et)
+{
+  switch (et)
+    {
+    case FIFO_EVENT_APP_RX:
+      return "FIFO_EVENT_APP_RX";
+    case FIFO_EVENT_APP_TX:
+      return "FIFO_EVENT_APP_TX";
+    case FIFO_EVENT_DISCONNECT:
+      return "FIFO_EVENT_DISCONNECT";
+    case FIFO_EVENT_BUILTIN_RX:
+      return "FIFO_EVENT_BUILTIN_RX";
+    case FIFO_EVENT_RPC:
+      return "FIFO_EVENT_RPC";
+    default:
+      return "UNKNOWN FIFO EVENT";
+    }
+}
+
+typedef enum
+{
+  SESSION_MQ_IO_EVT_RING,
+  SESSION_MQ_CTRL_EVT_RING,
+  SESSION_MQ_N_RINGS
+} session_mq_rings_e;
+
+typedef struct
+{
+  void *fp;
+  void *arg;
+} session_rpc_args_t;
+
+/* *INDENT-OFF* */
+typedef struct
+{
+  u8 event_type;
+  u8 postponed;
+  union
+  {
+    svm_fifo_t *fifo;
+    session_handle_t session_handle;
+    session_rpc_args_t rpc_args;
+    struct
+    {
+      u8 data[0];
+    };
+  };
+} __clib_packed session_event_t;
+/* *INDENT-ON* */
+
+#define SESSION_MSG_NULL { }
+
+typedef struct session_dgram_pre_hdr_
+{
+  u32 data_length;
+  u32 data_offset;
+} session_dgram_pre_hdr_t;
+
+/* *INDENT-OFF* */
+typedef CLIB_PACKED (struct session_dgram_header_
+{
+  u32 data_length;
+  u32 data_offset;
+  ip46_address_t rmt_ip;
+  ip46_address_t lcl_ip;
+  u16 rmt_port;
+  u16 lcl_port;
+  u8 is_ip4;
+}) session_dgram_hdr_t;
+/* *INDENT-ON* */
+
+#define SESSION_CONN_ID_LEN 37
+#define SESSION_CONN_HDR_LEN 45
+
+STATIC_ASSERT (sizeof (session_dgram_hdr_t) == (SESSION_CONN_ID_LEN + 8),
+	       "session conn id wrong length");
 #endif /* SRC_VNET_SESSION_SESSION_TYPES_H_ */
 
 /*