Bug#23541550 AUDIT API PROVIDE CONNECTION_TYPE FOR MYSQL_AUDIT_CONNECTION_CONNECT EVENT ONLY

Problem:
========

Connection type field is available for the connect event only of the connection class.
Due to lack of filtering mechanism, all 3 events were always available in the audit log
file, so anyone could track connection_type by checking connect event only. By that time
audit log filtering mechanism was introduced and one can create a filter that will log
disconnect or chage user events. In this case, connection_type information is not available.
Additionally, a filter that filters connection_type of the disconnect or change user events
could not be created.

Fix:

Connection type field is available in connect/disconnect/change_user events of the connection class.

Reviewed-by:
============
Arun Kuruvila <[email protected]>
Kristofer Pettersson <[email protected]>

Author: maras007

sql/sql_audit.cc

@@ -395,10 +395,7 @@ int mysql_audit_notify(THD *thd, mysql_event_connection_subclass_t subclass,
   event.ip.length= thd->security_context()->ip().length;
   event.database.str= thd->db().str;
   event.database.length= thd->db().length;
-
-  /* Keep this for backward compatibility. */
-  event.connection_type= subclass == MYSQL_AUDIT_CONNECTION_CONNECT ?
-                         thd->get_vio_type() : NO_VIO_TYPE;
+  event.connection_type= thd->get_vio_type();
 
   if (subclass == MYSQL_AUDIT_CONNECTION_DISCONNECT)
   {