session: cleanup part 2

Move app worker logic to app_worker.c

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

1 files changed, 1116 insertions, 0 deletions

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:
+ */