session: support for cl port reuse

Adds support for connectionless listener port reuse. Until now, cl
listeners had fifos allocated to them and therefore only one app worker
could ever listen, i.e., a session cannot have multiple fifos.

To circumvent the limitation, this separates the fifos from the listener
by allocating new cl sessions for each app worker that reuses the app
listener. Flows are hashed to app worker cl sessions but, for now, this
is not a consistent/fixed hash.

Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: Ic6533cd47f2765903669f88c288bd592fb17a19e

1 files changed, 61 insertions, 13 deletions

diff --git a/src/vnet/session/application_worker.c b/src/vnet/session/application_worker.c
index 960d916133f..ea5a4db7fd5 100644
--- a/src/vnet/session/application_worker.c
+++ b/src/vnet/session/application_worker.c
@@ -186,12 +186,67 @@ 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_w_session (ls);
+  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_w_session (ls);
+
+  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;
 
@@ -202,12 +257,9 @@ app_worker_init_listener (app_worker_t * app_wrk, session_t * ls)
   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;
 }
 
@@ -276,12 +328,8 @@ 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);