Right now it is very hard to figure out whether we should be calling the
connect callback or the disconnect callback. So refactor as follows:
- Connect callback is only called once the net is actually up
- Disconnect callback is called once ppp is down, with a reason
for why it is so.
Marcel: recording right now only works for PPP, so we'd need some sort
of multi-protocol support.
So for now expose set_recording to be used through the main PPP object.
HDLC object recording support needs to be extended.
The connect callback was not giving enough information and the
information it was providing was not in a convenient form.
- Provide the ppp interface name (e.g. tun0)
- Provide ip, dns1 & dns2 as strings
- Do not send the ppp structure in the callback, it is most likely
present in the user data anyway