1 files changed, 288 insertions, 146 deletions

diff --git a/src/vnet/session/application_worker.c b/src/vnet/session/application_worker.c
index be8a9e86bd5..befdb7c7002 100644
--- a/src/vnet/session/application_worker.c
+++ b/src/vnet/session/application_worker.c
@@ -26,6 +26,7 @@ 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;
@@ -33,6 +34,8 @@ app_worker_alloc (application_t * app)
   app_wrk->wrk_map_index = ~0;
   app_wrk->connects_seg_manager = APP_INVALID_SEGMENT_MANAGER_INDEX;
   clib_spinlock_init (&app_wrk->detached_seg_managers_lock);
+  vec_validate (app_wrk->wrk_evts, vlib_num_workers ());
+  vec_validate (app_wrk->wrk_mq_congested, vlib_num_workers ());
   APP_DBG ("New app %v worker %u", app->name, app_wrk->wrk_index);
   return app_wrk;
 }
@@ -55,26 +58,34 @@ void
 app_worker_free (app_worker_t * app_wrk)
 {
   application_t *app = application_get (app_wrk->app_index);
+  session_handle_t handle, *handles = 0, *sh;
   vnet_unlisten_args_t _a, *a = &_a;
-  u64 handle, *handles = 0, *sm_indices = 0;
   segment_manager_t *sm;
-  session_handle_t *sh;
+  u64 *sm_indices = 0;
   session_t *ls;
   u32 sm_index;
   int i;
 
   /*
+   * Cleanup vpp wrk events
+   */
+  app_worker_del_all_events (app_wrk);
+  for (i = 0; i < vec_len (app_wrk->wrk_evts); i++)
+    clib_fifo_free (app_wrk->wrk_evts[i]);
+
+  vec_free (app_wrk->wrk_evts);
+  vec_free (app_wrk->wrk_mq_congested);
+
+  /*
    *  Listener cleanup
    */
 
-  /* *INDENT-OFF* */
   hash_foreach (handle, sm_index, app_wrk->listeners_table, ({
     ls = listen_session_get_from_handle (handle);
     vec_add1 (handles, app_listen_session_handle (ls));
     vec_add1 (sm_indices, sm_index);
     sm = segment_manager_get (sm_index);
   }));
-  /* *INDENT-ON* */
 
   for (i = 0; i < vec_len (handles); i++)
     {
@@ -91,7 +102,7 @@ app_worker_free (app_worker_t * app_wrk)
 	  segment_manager_init_free (sm);
 	}
     }
-  vec_reset_length (handles);
+  vec_free (handles);
   vec_free (sm_indices);
   hash_free (app_wrk->listeners_table);
 
@@ -175,31 +186,85 @@ app_worker_alloc_session_fifos (segment_manager_t * sm, session_t * s)
 }
 
 int
+app_worker_alloc_wrk_cl_session (app_worker_t *app_wrk, session_t *ls)
+{
+  svm_fifo_t *rx_fifo = 0, *tx_fifo = 0;
+  segment_manager_t *sm;
+  session_handle_t lsh;
+  app_listener_t *al;
+  session_t *s;
+
+  al = app_listener_get (ls->al_index);
+  sm = app_worker_get_listen_segment_manager (app_wrk, ls);
+  lsh = session_handle (ls);
+
+  s = session_alloc (0 /* listener on main worker */);
+  session_set_state (s, SESSION_STATE_LISTENING);
+  s->flags |= SESSION_F_IS_CLESS;
+  s->app_wrk_index = app_wrk->wrk_index;
+  ls = session_get_from_handle (lsh);
+  s->session_type = ls->session_type;
+  s->connection_index = ls->connection_index;
+
+  segment_manager_alloc_session_fifos (sm, s->thread_index, &rx_fifo,
+				       &tx_fifo);
+
+  rx_fifo->shr->master_session_index = s->session_index;
+  rx_fifo->master_thread_index = s->thread_index;
+
+  tx_fifo->shr->master_session_index = s->session_index;
+  tx_fifo->master_thread_index = s->thread_index;
+
+  s->rx_fifo = rx_fifo;
+  s->tx_fifo = tx_fifo;
+
+  vec_validate (al->cl_listeners, app_wrk->wrk_map_index);
+  al->cl_listeners[app_wrk->wrk_map_index] = s->session_index;
+
+  return 0;
+}
+
+void
+app_worker_free_wrk_cl_session (app_worker_t *app_wrk, session_t *ls)
+{
+  app_listener_t *al;
+  session_t *s;
+
+  al = app_listener_get (ls->al_index);
+
+  s = app_listener_get_wrk_cl_session (al, app_wrk->wrk_map_index);
+  segment_manager_dealloc_fifos (s->rx_fifo, s->tx_fifo);
+  session_free (s);
+
+  al->cl_listeners[app_wrk->wrk_map_index] = SESSION_INVALID_INDEX;
+}
+
+int
 app_worker_init_listener (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. */
+   * have fifos allocated by the same segment manager.
+   * TODO(fcoras): limit memory consumption by cless listeners */
   if (!(sm = app_worker_alloc_segment_manager (app_wrk)))
     return SESSION_E_ALLOC;
 
+  /* Once the first segment is mapped, don't remove it until unlisten */
+  sm->first_is_protected = 1;
+
   /* 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 (transport_connection_is_cless (session_get_transport (ls)))
-    {
-      if (ls->rx_fifo)
-	return SESSION_E_NOSUPPORT;
-      return app_worker_alloc_session_fifos (sm, ls);
-    }
+  if (ls->flags & SESSION_F_IS_CLESS)
+    return app_worker_alloc_wrk_cl_session (app_wrk, ls);
+
   return 0;
 }
 
-int
-app_worker_start_listen (app_worker_t * app_wrk,
-			 app_listener_t * app_listener)
+session_error_t
+app_worker_start_listen (app_worker_t *app_wrk, app_listener_t *app_listener)
 {
   session_t *ls;
   int rv;
@@ -263,17 +328,14 @@ app_worker_stop_listen_session (app_worker_t * app_wrk, session_t * ls)
   if (PREDICT_FALSE (!sm_indexp))
     return;
 
-  /* Dealloc fifos, if any (dgram listeners) */
-  if (ls->rx_fifo)
-    {
-      segment_manager_dealloc_fifos (ls->rx_fifo, ls->tx_fifo);
-      ls->tx_fifo = ls->rx_fifo = 0;
-    }
+  if (ls->flags & SESSION_F_IS_CLESS)
+    app_worker_free_wrk_cl_session (app_wrk, ls);
 
   /* Try to cleanup segment manager */
   sm = segment_manager_get (*sm_indexp);
   if (sm)
     {
+      sm->first_is_protected = 0;
       segment_manager_app_detach (sm);
       if (!segment_manager_has_fifos (sm))
 	{
@@ -334,8 +396,10 @@ app_worker_init_accepted (session_t * s)
 
   listener = listen_session_get_from_handle (s->listener_handle);
   app_wrk = application_listener_select_worker (listener);
-  s->app_wrk_index = app_wrk->wrk_index;
+  if (PREDICT_FALSE (app_worker_mq_is_congested (app_wrk)))
+    return -1;
 
+  s->app_wrk_index = app_wrk->wrk_index;
   app = application_get (app_wrk->app_index);
   if (app->cb_fns.fifo_tuning_callback)
     s->flags |= SESSION_F_CUSTOM_FIFO_TUNING;
@@ -348,10 +412,35 @@ app_worker_init_accepted (session_t * s)
 }
 
 int
+app_worker_listened_notify (app_worker_t *app_wrk, session_handle_t alsh,
+			    u32 opaque, session_error_t err)
+{
+  session_event_t evt = { .event_type = SESSION_CTRL_EVT_BOUND,
+			  .as_u64[0] = alsh,
+			  .as_u64[1] = (u64) opaque << 32 | (u32) err };
+
+  app_worker_add_event_custom (app_wrk, 0 /* thread index */, &evt);
+
+  return 0;
+}
+
+int
+app_worker_unlisten_reply (app_worker_t *app_wrk, session_handle_t sh,
+			   u32 opaque, session_error_t err)
+{
+  session_event_t evt = { .event_type = SESSION_CTRL_EVT_UNLISTEN_REPLY,
+			  .as_u64[0] = sh,
+			  .as_u64[1] = (u64) opaque << 32 | (u32) err };
+
+  app_worker_add_event_custom (app_wrk, 0 /* thread index */, &evt);
+  return 0;
+}
+
+int
 app_worker_accept_notify (app_worker_t * app_wrk, session_t * s)
 {
-  application_t *app = application_get (app_wrk->app_index);
-  return app->cb_fns.session_accept_callback (s);
+  app_worker_add_event (app_wrk, s, SESSION_CTRL_EVT_ACCEPTED);
+  return 0;
 }
 
 int
@@ -365,7 +454,7 @@ app_worker_init_connected (app_worker_t * app_wrk, session_t * s)
 
   /* Allocate fifos for session, unless the app is a builtin proxy */
   if (application_is_builtin_proxy (app))
-    return 0;
+    return app->cb_fns.proxy_alloc_session_fifos (s);
 
   sm = app_worker_get_connect_segment_manager (app_wrk);
   return app_worker_alloc_session_fifos (sm, s);
@@ -375,9 +464,13 @@ int
 app_worker_connect_notify (app_worker_t * app_wrk, session_t * s,
 			   session_error_t err, u32 opaque)
 {
-  application_t *app = application_get (app_wrk->app_index);
-  return app->cb_fns.session_connected_callback (app_wrk->wrk_index, opaque,
-						 s, err);
+  session_event_t evt = { .event_type = SESSION_CTRL_EVT_CONNECTED,
+			  .as_u64[0] = s ? s->session_index : ~0,
+			  .as_u64[1] = (u64) opaque << 32 | (u32) err };
+  u32 thread_index = s ? s->thread_index : vlib_get_thread_index ();
+
+  app_worker_add_event_custom (app_wrk, thread_index, &evt);
+  return 0;
 }
 
 int
@@ -385,7 +478,7 @@ app_worker_add_half_open (app_worker_t *app_wrk, session_handle_t sh)
 {
   session_handle_t *shp;
 
-  ASSERT (vlib_get_thread_index () == 0);
+  ASSERT (session_vlib_thread_is_cl_thread ());
   pool_get (app_wrk->half_open_table, shp);
   *shp = sh;
 
@@ -395,36 +488,28 @@ app_worker_add_half_open (app_worker_t *app_wrk, session_handle_t sh)
 int
 app_worker_del_half_open (app_worker_t *app_wrk, session_t *s)
 {
-  application_t *app = application_get (app_wrk->app_index);
-  ASSERT (vlib_get_thread_index () <= 1);
-  pool_put_index (app_wrk->half_open_table, s->ho_index);
-  if (app->cb_fns.half_open_cleanup_callback)
-    app->cb_fns.half_open_cleanup_callback (s);
+  app_worker_add_event (app_wrk, s, SESSION_CTRL_EVT_HALF_CLEANUP);
   return 0;
 }
 
 int
 app_worker_close_notify (app_worker_t * app_wrk, session_t * s)
 {
-  application_t *app = application_get (app_wrk->app_index);
-  app->cb_fns.session_disconnect_callback (s);
+  app_worker_add_event (app_wrk, s, SESSION_CTRL_EVT_DISCONNECTED);
   return 0;
 }
 
 int
 app_worker_transport_closed_notify (app_worker_t * app_wrk, session_t * s)
 {
-  application_t *app = application_get (app_wrk->app_index);
-  if (app->cb_fns.session_transport_closed_callback)
-    app->cb_fns.session_transport_closed_callback (s);
+  app_worker_add_event (app_wrk, s, SESSION_CTRL_EVT_TRANSPORT_CLOSED);
   return 0;
 }
 
 int
 app_worker_reset_notify (app_worker_t * app_wrk, session_t * s)
 {
-  application_t *app = application_get (app_wrk->app_index);
-  app->cb_fns.session_reset_callback (s);
+  app_worker_add_event (app_wrk, s, SESSION_CTRL_EVT_RESET);
   return 0;
 }
 
@@ -432,29 +517,33 @@ int
 app_worker_cleanup_notify (app_worker_t * app_wrk, session_t * s,
 			   session_cleanup_ntf_t ntf)
 {
-  application_t *app = application_get (app_wrk->app_index);
-  if (app->cb_fns.session_cleanup_callback)
-    app->cb_fns.session_cleanup_callback (s, ntf);
+  session_event_t evt = { .event_type = SESSION_CTRL_EVT_CLEANUP,
+			  .as_u64[0] = (u64) ntf << 32 | s->session_index,
+			  .as_u64[1] = pointer_to_uword (session_cleanup) };
+
+  app_worker_add_event_custom (app_wrk, s->thread_index, &evt);
+
   return 0;
 }
 
 int
-app_worker_builtin_rx (app_worker_t * app_wrk, session_t * s)
+app_worker_cleanup_notify_custom (app_worker_t *app_wrk, session_t *s,
+				  session_cleanup_ntf_t ntf,
+				  void (*cleanup_cb) (session_t *s))
 {
-  application_t *app = application_get (app_wrk->app_index);
-  app->cb_fns.builtin_app_rx_callback (s);
+  session_event_t evt = { .event_type = SESSION_CTRL_EVT_CLEANUP,
+			  .as_u64[0] = (u64) ntf << 32 | s->session_index,
+			  .as_u64[1] = pointer_to_uword (cleanup_cb) };
+
+  app_worker_add_event_custom (app_wrk, s->thread_index, &evt);
+
   return 0;
 }
 
 int
-app_worker_builtin_tx (app_worker_t * app_wrk, session_t * s)
+app_worker_rx_notify (app_worker_t *app_wrk, session_t *s)
 {
-  application_t *app = application_get (app_wrk->app_index);
-
-  if (!app->cb_fns.builtin_app_tx_callback)
-    return 0;
-
-  app->cb_fns.builtin_app_tx_callback (s);
+  app_worker_add_event (app_wrk, s, SESSION_IO_EVT_RX);
   return 0;
 }
 
@@ -462,8 +551,11 @@ int
 app_worker_migrate_notify (app_worker_t * app_wrk, session_t * s,
 			   session_handle_t new_sh)
 {
-  application_t *app = application_get (app_wrk->app_index);
-  app->cb_fns.session_migrate_callback (s, new_sh);
+  session_event_t evt = { .event_type = SESSION_CTRL_EVT_MIGRATED,
+			  .as_u64[0] = s->session_index,
+			  .as_u64[1] = new_sh };
+
+  app_worker_add_event_custom (app_wrk, s->thread_index, &evt);
   return 0;
 }
 
@@ -472,6 +564,7 @@ app_worker_own_session (app_worker_t * app_wrk, session_t * s)
 {
   segment_manager_t *sm;
   svm_fifo_t *rxf, *txf;
+  int rv;
 
   if (s->session_state == SESSION_STATE_LISTENING)
     return application_change_listener_owner (s, app_wrk);
@@ -488,8 +581,8 @@ app_worker_own_session (app_worker_t * app_wrk, session_t * s)
   s->tx_fifo = 0;
 
   sm = app_worker_get_connect_segment_manager (app_wrk);
-  if (app_worker_alloc_session_fifos (sm, s))
-    return -1;
+  if ((rv = app_worker_alloc_session_fifos (sm, s)))
+    return rv;
 
   if (!svm_fifo_is_empty_cons (rxf))
     svm_fifo_clone (s->rx_fifo, rxf);
@@ -506,6 +599,9 @@ int
 app_worker_connect_session (app_worker_t *app_wrk, session_endpoint_cfg_t *sep,
 			    session_handle_t *rsh)
 {
+  if (PREDICT_FALSE (app_worker_mq_is_congested (app_wrk)))
+    return SESSION_E_REFUSED;
+
   sep->app_wrk_index = app_wrk->wrk_index;
 
   return session_open (sep, rsh);
@@ -549,14 +645,12 @@ app_worker_first_listener (app_worker_t * app_wrk, u8 fib_proto,
   sst = session_type_from_proto_and_ip (transport_proto,
 					fib_proto == FIB_PROTOCOL_IP4);
 
-  /* *INDENT-OFF* */
    hash_foreach (handle, sm_index, app_wrk->listeners_table, ({
      listener = listen_session_get_from_handle (handle);
      if (listener->session_type == sst
 	 && !(listener->flags & SESSION_F_PROXY))
        return listener;
    }));
-  /* *INDENT-ON* */
 
   return 0;
 }
@@ -573,13 +667,11 @@ app_worker_proxy_listener (app_worker_t * app_wrk, u8 fib_proto,
   sst = session_type_from_proto_and_ip (transport_proto,
 					fib_proto == FIB_PROTOCOL_IP4);
 
-  /* *INDENT-OFF* */
    hash_foreach (handle, sm_index, app_wrk->listeners_table, ({
      listener = listen_session_get_from_handle (handle);
      if (listener->session_type == sst && (listener->flags & SESSION_F_PROXY))
        return listener;
    }));
-  /* *INDENT-ON* */
 
   return 0;
 }
@@ -590,130 +682,178 @@ app_worker_proxy_listener (app_worker_t * app_wrk, u8 fib_proto,
 int
 app_worker_add_segment_notify (app_worker_t * app_wrk, u64 segment_handle)
 {
-  application_t *app = application_get (app_wrk->app_index);
+  session_event_t evt = { .event_type = SESSION_CTRL_EVT_APP_ADD_SEGMENT,
+			  .as_u64[1] = segment_handle };
 
-  return app->cb_fns.add_segment_callback (app_wrk->wrk_index,
-					   segment_handle);
+  app_worker_add_event_custom (app_wrk, vlib_get_thread_index (), &evt);
+
+  return 0;
 }
 
 int
 app_worker_del_segment_notify (app_worker_t * app_wrk, u64 segment_handle)
 {
-  application_t *app = application_get (app_wrk->app_index);
-  return app->cb_fns.del_segment_callback (app_wrk->wrk_index,
-					   segment_handle);
-}
+  session_event_t evt = { .event_type = SESSION_CTRL_EVT_APP_DEL_SEGMENT,
+			  .as_u64[1] = segment_handle };
 
-static inline u8
-app_worker_application_is_builtin (app_worker_t * app_wrk)
-{
-  return app_wrk->app_is_builtin;
+  app_worker_add_event_custom (app_wrk, vlib_get_thread_index (), &evt);
+
+  return 0;
 }
 
-static inline int
-app_send_io_evt_rx (app_worker_t * app_wrk, session_t * s)
+static int
+app_wrk_send_fd (app_worker_t *app_wrk, int fd)
 {
-  session_event_t *evt;
-  svm_msg_q_msg_t msg;
-  svm_msg_q_t *mq;
+  if (!appns_sapi_enabled ())
+    {
+      vl_api_registration_t *reg;
+      clib_error_t *error;
 
-  if (app_worker_application_is_builtin (app_wrk))
-    return app_worker_builtin_rx (app_wrk, s);
+      reg =
+	vl_mem_api_client_index_to_registration (app_wrk->api_client_index);
+      if (!reg)
+	{
+	  clib_warning ("no api registration for client: %u",
+			app_wrk->api_client_index);
+	  return -1;
+	}
 
-  if (svm_fifo_has_event (s->rx_fifo))
-    return 0;
+      if (vl_api_registration_file_index (reg) == VL_API_INVALID_FI)
+	return -1;
 
-  mq = app_wrk->event_queue;
-  svm_msg_q_lock (mq);
+      error = vl_api_send_fd_msg (reg, &fd, 1);
+      if (error)
+	{
+	  clib_error_report (error);
+	  return -1;
+	}
 
-  if (PREDICT_FALSE (svm_msg_q_is_full (mq)))
-    {
-      clib_warning ("evt q full");
-      svm_msg_q_unlock (mq);
-      return -1;
+      return 0;
     }
 
-  if (PREDICT_FALSE (svm_msg_q_ring_is_full (mq, SESSION_MQ_IO_EVT_RING)))
+  app_sapi_msg_t smsg = { 0 };
+  app_namespace_t *app_ns;
+  clib_error_t *error;
+  application_t *app;
+  clib_socket_t *cs;
+  u32 cs_index;
+
+  app = application_get (app_wrk->app_index);
+  app_ns = app_namespace_get (app->ns_index);
+  cs_index = appns_sapi_handle_sock_index (app_wrk->api_client_index);
+  cs = appns_sapi_get_socket (app_ns, cs_index);
+  if (PREDICT_FALSE (!cs))
+    return -1;
+
+  /* There's no payload for the message only the type */
+  smsg.type = APP_SAPI_MSG_TYPE_SEND_FDS;
+  error = clib_socket_sendmsg (cs, &smsg, sizeof (smsg), &fd, 1);
+  if (error)
     {
-      clib_warning ("evt q rings full");
-      svm_msg_q_unlock (mq);
+      clib_error_report (error);
       return -1;
     }
 
-  msg = svm_msg_q_alloc_msg_w_ring (mq, SESSION_MQ_IO_EVT_RING);
-  evt = (session_event_t *) svm_msg_q_msg_data (mq, &msg);
-  evt->session_index = s->rx_fifo->shr->client_session_index;
-  evt->event_type = SESSION_IO_EVT_RX;
-
-  (void) svm_fifo_set_event (s->rx_fifo);
-  svm_msg_q_add_and_unlock (mq, &msg);
-
   return 0;
 }
 
-static inline int
-app_send_io_evt_tx (app_worker_t * app_wrk, session_t * s)
+void
+app_worker_add_event (app_worker_t *app_wrk, session_t *s,
+		      session_evt_type_t evt_type)
 {
-  svm_msg_q_t *mq;
   session_event_t *evt;
-  svm_msg_q_msg_t msg;
 
-  if (app_worker_application_is_builtin (app_wrk))
-    return app_worker_builtin_tx (app_wrk, s);
+  ASSERT (s->thread_index == vlib_get_thread_index ());
+  clib_fifo_add2 (app_wrk->wrk_evts[s->thread_index], evt);
+  evt->session_index = s->session_index;
+  evt->event_type = evt_type;
+  evt->postponed = 0;
 
-  mq = app_wrk->event_queue;
-  svm_msg_q_lock (mq);
-
-  if (PREDICT_FALSE (svm_msg_q_is_full (mq)))
+  /* First event for this app_wrk. Schedule it for handling in session input */
+  if (clib_fifo_elts (app_wrk->wrk_evts[s->thread_index]) == 1)
     {
-      clib_warning ("evt q full");
-      svm_msg_q_unlock (mq);
-      return -1;
+      session_worker_t *wrk = session_main_get_worker (s->thread_index);
+      session_wrk_program_app_wrk_evts (wrk, app_wrk->wrk_index);
     }
+}
+
+void
+app_worker_add_event_custom (app_worker_t *app_wrk, u32 thread_index,
+			     session_event_t *evt)
+{
+  clib_fifo_add1 (app_wrk->wrk_evts[thread_index], *evt);
 
-  if (PREDICT_FALSE (svm_msg_q_ring_is_full (mq, SESSION_MQ_IO_EVT_RING)))
+  /* First event for this app_wrk. Schedule it for handling in session input */
+  if (clib_fifo_elts (app_wrk->wrk_evts[thread_index]) == 1)
     {
-      clib_warning ("evt q rings full");
-      svm_msg_q_unlock (mq);
-      return -1;
+      session_worker_t *wrk = session_main_get_worker (thread_index);
+      session_wrk_program_app_wrk_evts (wrk, app_wrk->wrk_index);
     }
+}
 
-  msg = svm_msg_q_alloc_msg_w_ring (mq, SESSION_MQ_IO_EVT_RING);
-  evt = (session_event_t *) svm_msg_q_msg_data (mq, &msg);
-  evt->event_type = SESSION_IO_EVT_TX;
-  evt->session_index = s->tx_fifo->shr->client_session_index;
+always_inline void
+app_wrk_send_ctrl_evt_inline (app_worker_t *app_wrk, u8 evt_type, void *msg,
+			      u32 msg_len, int fd)
+{
+  svm_msg_q_msg_t _mq_msg, *mq_msg = &_mq_msg;
+  svm_msg_q_t *mq = app_wrk->event_queue;
+  session_event_t *evt;
 
-  svm_msg_q_add_and_unlock (mq, &msg);
-  return 0;
+  ASSERT (!svm_msg_q_or_ring_is_full (mq, SESSION_MQ_CTRL_EVT_RING));
+  *mq_msg = svm_msg_q_alloc_msg_w_ring (mq, SESSION_MQ_CTRL_EVT_RING);
+
+  evt = svm_msg_q_msg_data (mq, mq_msg);
+  clib_memset (evt, 0, sizeof (*evt));
+  evt->event_type = evt_type;
+  clib_memcpy_fast (evt->data, msg, msg_len);
+
+  if (fd != -1)
+    app_wrk_send_fd (app_wrk, fd);
+
+  svm_msg_q_add_raw (mq, mq_msg);
+}
+
+void
+app_wrk_send_ctrl_evt_fd (app_worker_t *app_wrk, u8 evt_type, void *msg,
+			  u32 msg_len, int fd)
+{
+  app_wrk_send_ctrl_evt_inline (app_wrk, evt_type, msg, msg_len, fd);
 }
 
-/* *INDENT-OFF* */
-typedef int (app_send_evt_handler_fn) (app_worker_t *app,
-				       session_t *s);
-static app_send_evt_handler_fn * const app_send_evt_handler_fns[2] = {
-    app_send_io_evt_rx,
-    app_send_io_evt_tx,
-};
-/* *INDENT-ON* */
+void
+app_wrk_send_ctrl_evt (app_worker_t *app_wrk, u8 evt_type, void *msg,
+		       u32 msg_len)
+{
+  app_wrk_send_ctrl_evt_inline (app_wrk, evt_type, msg, msg_len, -1);
+}
 
-/**
- * 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)
+u8
+app_worker_mq_wrk_is_congested (app_worker_t *app_wrk, u32 thread_index)
+{
+  return app_wrk->wrk_mq_congested[thread_index] > 0;
+}
+
+void
+app_worker_set_mq_wrk_congested (app_worker_t *app_wrk, u32 thread_index)
+{
+  clib_atomic_fetch_add_relax (&app_wrk->mq_congested, 1);
+  ASSERT (thread_index == vlib_get_thread_index ());
+  app_wrk->wrk_mq_congested[thread_index] = 1;
+}
+
+void
+app_worker_unset_wrk_mq_congested (app_worker_t *app_wrk, u32 thread_index)
 {
-  return app_send_evt_handler_fns[evt_type] (app, s);
+  clib_atomic_fetch_sub_relax (&app_wrk->mq_congested, 1);
+  ASSERT (thread_index == vlib_get_thread_index ());
+  app_wrk->wrk_mq_congested[thread_index] = 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);
+  session_handle_t handle = va_arg (*args, u64);
   u32 sm_index = va_arg (*args, u32);
   int verbose = va_arg (*args, int);
   session_t *listener;
@@ -760,10 +900,12 @@ 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);
+  s = format (s,
+	      "%U wrk-index %u app-index %u map-index %u "
+	      "api-client-index %d mq-cong %u\n",
+	      format_white_space, indent, app_wrk->wrk_index,
+	      app_wrk->app_index, app_wrk->wrk_map_index,
+	      app_wrk->api_client_index, app_wrk->mq_congested);
   return s;
 }