[Networkmanager] Cancel connection up/connection down from dispatcher scripts or other hooks?

[Farblos]

Hi.

I can imagine some use cases where it would be useful to actively cancel a user request to bring up/down some connection, regardless of the UI used by the user:

- close open files on networked devices before connection is lost

- prevent from using a certain VPN if some conditions are not fulfilled

The pre-up/pre-down hooks (NetworkManager-dispatcher(8)) seem to be close to that requirement, but from what I understand I can only delay connection up/down in these hooks and not cancel or prevent them.

Is there anything else?

Thanks!