WG: Extension using the current connection handle

Hello
I have written a extension in postgres to call a Oracle Stored procedure.
We have a Postgres table holding the usernames and password related to the Oracle SID.

In my extension I wanted to select the username and password out of this table.
Do I have to make a new Postgres connection or can I somehow use the current connection handel from the session Where
theextension will be called?
 

Regards
Wolfgang