session: move ctrl messages from bapi to mq

Type:refactor

Moves connect, disconnect, bind, unbind and app detach to message
queue from binary api. Simplifies app/vcl interaction with the session
layer since all session control messages are now handled over the mq.

Add/del segment messages require internal C api changes which affect all
builtin applications. They'll be moved in a different patch and might
not be back portable to 19.08.

Change-Id: I93f6d18e551b024effa75d47f5ff25f23ba8aff5
Signed-off-by: Florin Coras <fcoras@cisco.com>
diff --git a/src/vnet/session/session.h b/src/vnet/session/session.h
index de44bed..04fdebe 100644
--- a/src/vnet/session/session.h
+++ b/src/vnet/session/session.h
@@ -62,12 +62,19 @@
   session_dgram_hdr_t hdr;
 } session_tx_context_t;
 
+#define SESSION_CTRL_MSG_MAX_SIZE 64
+
 typedef struct session_evt_elt
 {
   clib_llist_anchor_t evt_list;
   session_event_t evt;
 } session_evt_elt_t;
 
+typedef struct session_ctrl_evt_data_
+{
+  u8 data[SESSION_CTRL_MSG_MAX_SIZE];
+} session_evt_ctrl_data_t;
+
 typedef struct session_worker_
 {
   CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
@@ -96,6 +103,9 @@
   /** Pool of session event list elements */
   session_evt_elt_t *event_elts;
 
+  /** Pool of ctrl events data buffers */
+  session_evt_ctrl_data_t *ctrl_evts_data;
+
   /** Head of control events list */
   clib_llist_index_t ctrl_head;
 
@@ -207,6 +217,14 @@
 		       pool_elt_at_index (wrk->event_elts, wrk->old_head));
 }
 
+static inline u32
+session_evt_ctrl_data_alloc (session_worker_t * wrk)
+{
+  session_evt_ctrl_data_t *data;
+  pool_get (wrk->ctrl_evts_data, data);
+  return (data - wrk->ctrl_evts_data);
+}
+
 static inline session_evt_elt_t *
 session_evt_alloc_ctrl (session_worker_t * wrk)
 {
@@ -217,6 +235,20 @@
   return elt;
 }
 
+static inline void *
+session_evt_ctrl_data (session_worker_t * wrk, session_evt_elt_t * elt)
+{
+  return (void *) (pool_elt_at_index (wrk->ctrl_evts_data,
+				      elt->evt.ctrl_data_index));
+}
+
+static inline void
+session_evt_ctrl_data_free (session_worker_t * wrk, session_evt_elt_t * elt)
+{
+  ASSERT (elt->evt.event_type > SESSION_IO_EVT_BUILTIN_TX);
+  pool_put_index (wrk->ctrl_evts_data, elt->evt.ctrl_data_index);
+}
+
 static inline session_evt_elt_t *
 session_evt_alloc_new (session_worker_t * wrk)
 {