session: add api cb for listen and unlisten

Type: improvement

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I28ccebf4d2f0728dd174ab3ee77a0d7ad4b90951
diff --git a/src/vnet/session/application_interface.h b/src/vnet/session/application_interface.h
index b41f7a4..c7ed528 100644
--- a/src/vnet/session/application_interface.h
+++ b/src/vnet/session/application_interface.h
@@ -62,6 +62,13 @@
   /** Notify app that session pool migration happened */
   void (*session_migrate_callback) (session_t * s, session_handle_t new_sh);
 
+  /** Notify app (external only) that listen was processed */
+  int (*session_listened_callback) (u32 app_wrk_index, u32 api_context,
+				    session_handle_t handle, int rv);
+  /** Notify app (external only) that unlisten was processed */
+  void (*session_unlistened_callback) (u32 app_wrk_index, session_handle_t sh,
+				       u32 context, int rv);
+
   /** Direct RX callback for built-in application */
   int (*builtin_app_rx_callback) (session_t * session);