Support for WSL2 v 2.0 in Mirrored mode

[Rybasum]

The new version of WSL2 (v2.0) offers Mirrored networking mode (https://devblogs.microsoft.com/commandline/windows-subsystem-for-linux-september-2023-update). In this mode usbipd can't attach:

usbipd wsl attach -i=0403:6001
usbipd: info: Device with hardware-id '0403:6001' found at busid '4-1'.
usbipd: error: The selected WSL distribution cannot be reached via the WSL virtual switch; try restarting the WSL distribution.

A workaround is this (in WSL2):

sudo usbip attach -r localhost --busid=4-1

but it is not very convenient...

[dorssel]

Thanks for the report!

@benmcmorran
I'll see if I can get this mode auto-detected and supported. Can you review the result? Or any pointers for a head start?

[Rybasum]

@dorssel I can't find a better way to tell in which networking mode WSL2 is, other than checking the version (should be 2.0.0 or newer) and the presence in the .wslconfig file of this:

[experimental]
networkingMode=mirrored

[benmcmorran]

I'm not currently working on WSL, but I can try to loop in a Microsoft engineer that is.

[benmcmorran]

Sounds like reading .wslconfig is the only way to detect mirrored mode for now, but the team is planning an improved detection mechanism for a future WSL release.

[craigloewen-msft]

@dorssel we are looking into a robust way to detect this and will share it as soon as it's available! :)

[craigloewen-msft]

@dorssel we added a binary called wslinfo into WSL that will be able to tell you the networking mode. Are you able to use this to determine if a user is running in mirrored mode and adjust accordingly?

https://github.com/microsoft/WSL/releases/tag/2.0.4

[Rybasum]

~$ wslinfo --networking-mode
mirrored

It seems to work!

[dorssel]

It seems to work!

Yes, I found the same. However ... usbipd needs to know the networking mode on the Windows (host) side. I have not yet decided if I want to run a remote (WSL) command (which may not be available...), just to get the information that is required on the Windows side, or instead parsing the option in .wslconfig.

In fact, I believe the whole WSL enumeration code needs a refactor. It is rather old, some stuff is no longer required. It was originally designed to determine the 'per-distro' IP address, which actually never worked, as the IP address is the same for all distros anyway, irrespective of the networking mode. In other words: the design doesn't really fit the purpose. Rewrite is incoming, but not very soon...

[Rybasum]

@dorssel Is the following helpful:

PS C:\Users\marci> wsl -e wslinfo --networking-mode
mirrored

[dorssel]

Not really, sorry. This is exactly what I was referring to. This is running a remote command, on the default distro, which may not even be running (or may not even be WSL 2).

[Rybasum]

@dorssel With wsl shut down, the command still works, albeit it takes ten seconds (needs to start wsl, I guess):

PS C:\Users\marci> wsl --shutdown
PS C:\Users\marci> wsl -e wslinfo --networking-mode
mirrored

The command indeed runs on the default distro, but .wslconfig is global, applies to all distros.
Other problems you cited are valid points, but I just wonder if running wsl -e wslinfo --networking-mode from inside usbipd on Windows might cover 90% of use cases. If the command fails - be it, print an error message ...?

[dorssel]

4.0.0 has been released, which supports mirrored networking mode.