[GSoC 2023] VPN Support Project Update #5

Tempered Optimism

So great news everyone, OpenVPN and the TUN/TAP driver is working on Haiku! While this is great news for the development of the project, I need to temper it with some problems that the project has encountered now. So first thing that I had to change first was going from TUN to TAP since OpenVPN wanted a Point-to-Point connection for the TUN driver and Point-to-Point isn’t quite a thing on Haiku yet. I had a lot of trouble with routing with TUN, so I moved onto TAP, and that seems to work… sort of. The main thing is that Haiku can be a client fine but it has some trouble being a server as OpenVPN can set the server up, and have a client OpenVPN connect to it (let us say the client is running Linux), but the client cannot ping the Haiku server. When I try to ping the server, ping will just say Destination Host Unreachable. Looking further into it using tcpdump, I realized that the client is trying to send ARP request to try and find the server and the Haiku server isn’t responding. Checking the Haiku side of things, I noticed that it wasn’t receiving the ARP requests to begin with so I have a hunch it might be the VirtualBox NAT Network I am using but I am not ruling out the possibility of the TAP driver or the TAP interface.

New Problems Going Forward

Along with the problem mentioned above, there are also some more peripheral issues that I want to solve as well including but not limited to:

1. If you ctrl+c during something on TUN/TAP interface
2. Interface does not go down and can stall the system for some reason if you do ifconfig delete tap0 for instance
3. Driver needs to be assigned dynamically
4. OpenVPN seems to run at 99% CPU usage

I am not particularly worried about issue 1 since that doesn’t seem to affect too much to begin with but problems 2 and 3 are of concern since they should be done before my time at GSoC is over. Unfortunately with problem number 4, that’s going to require a deeper dive into OpenVPN source code to find where it could be more efficient with the operating system which I don’t know I’ll have the time for.

I am happy to share that my project has made some really big progress, even if it brings up some more issues in the process but I felt that I was stuck in a rut with this project for a while so progress is progress! Thank you for reading my blog post and as always if you have anything to say then I would be happy to read it in the comments :)