Specify the callback function to use in the server for validating a
user via the SECURID mechanism. The function should return
GSASL_OK if user authenticated successfully,
GSASL_SECURID_SERVER_NEED_ADDITIONAL_PASSCODE if it wants another
passcode, GSASL_SECURID_SERVER_NEED_NEW_PIN if it wants a PIN
change, or an error. When (and only when)
GSASL_SECURID_SERVER_NEED_NEW_PIN is returned, suggestpin can be
populated with a PIN code the server suggests, and suggestpinlen
set to the length of the PIN. The function can be later retrieved
This function is part of the old callback interface.
The new interface uses gsasl_callback_set() to set the application
callback, and uses gsasl_callback() or gsasl_property_get() to
invoke the callback for certain properties.