Pass through socat device?

[unf0rg0tt3n]

Hi all,

Does anyoe know how I can passthrough a socat device to a VM?

I have a raspberry pi which has several USB devices.
I want to send the device over the network to a proxmox VM which cant run socat directly.
via ser2net I mentioned to publish the device. But how do I pass that through to my VM?

Cheers,
Dennis

 

[Stefan_R]

If you can receive the stream on your PVE host, you can forward it via a virtual serial device into the VM. Similar to this answer, but obviously only do it for your one VM and replace the corresponding side of the socat command with whatever network stream you want to receive.

 

[unf0rg0tt3n]

If you can receive the stream on your PVE host, you can forward it via a virtual serial device into the VM. Similar to this answer, but obviously only do it for your one VM and replace the corresponding side of the socat command with whatever network stream you want to receive.

I have read the post you sent.
Don't quite understand how it works.

I have passed through an USB stick to /dev/ttyACM0, then I added the following to my VM (vmid 109):

serial0: /dev/ttyACM0

But it doesn't show inside my VM, I guess it's not the correct way, but what would be?

Thanks!

 

[Stefan_R]

But it doesn't show inside my VM, I guess it's not the correct way, but what would be?

Since you mentioned ser2net before, I imagined a more complex setup. If your serial connection is available locally via a /dev device, then yes, this should work...

But it doesn't show inside my VM, I guess it's not the correct way, but what would be?

Bit more detail about how it doesn't work please... Any errors in the task log when you start the VM? Any messages in dmesg/journalctl (guest and host)? Do you just not see it in /dev on the guest? What do you see, i.e. 'ls -lA /dev' on the guest might help.

 

[unf0rg0tt3n]

Since you mentioned ser2net before, I imagined a more complex setup. If your serial connection is available locally via a /dev device, then yes, this should work...


Bit more detail about how it doesn't work please... Any errors in the task log when you start the VM? Any messages in dmesg/journalctl (guest and host)? Do you just not see it in /dev on the guest? What do you see, i.e. 'ls -lA /dev' on the guest might help.

I have found the device within /dev. it's named /dev/ttyACM0 journalctl and dmesg show no errors regarding this issue (only the ones when I tried usbip, which i doesnt anymore... old entries).

When is I started the VM everything boots and no trouble. When I check what devices are present in the VM, there are none.

 

[Stefan_R]

That is the same information as before. Please show the output of 'ls -lA' from within your VM. Note that even though it is called '/dev/ttyACM0' on your host, it will be called differently in your VM.

 

[unf0rg0tt3n]

That is the same information as before. Please show the output of 'ls -lA' from within your VM. Note that even though it is called '/dev/ttyACM0' on your host, it will be called differently in your VM.

This is with the /dev/ttyACM0 added as serial device:



this is with the serial device removed:

 

[Stefan_R]

Yeah so what's the problem then? /dev/ttyS0 clearly shows as part of the 'tty' group in the first image, meaning it is detected as a serial device. It should allow you to communicate with your USB device.

 

[unf0rg0tt3n]

Yeah so what's the problem then? /dev/ttyS0 clearly shows as part of the 'tty' group in the first image, meaning it is detected as a serial device. It should allow you to communicate with your USB device.

okay, so help me understand. When I remove the serial device from my configuration, it still shows the ttyS0. why is that then?

 

[Stefan_R]

Linux allocates a few /dev/ttySx device nodes for serial devices by default. These are not connected, file operations (e.g. echo abc > /dev/ttyS1) will fail. Once it's connected, udev kicks in and assigns the correct group ('tty' in this case) for the device node. You can even make more such unallocated device nodes, if you want - try mknod /dev/my-custom-tty-serial-node c 4 68.

 

[unf0rg0tt3n]

Linux allocates a few /dev/ttySx device nodes for serial devices by default. These are not connected, file operations (e.g. echo abc > /dev/ttyS1) will fail. Once it's connected, udev kicks in and assigns the correct group ('tty' in this case) for the device node. You can even make more such unallocated device nodes, if you want - try mknod /dev/my-custom-tty-serial-node c 4 68.

Thanks for all the help!
It still doesn't work, but I learned a lote though

 

[RHCPNG]

Thanks for all the help!
It still doesn't work, but I learned a lote though

Hi @unf0rg0tt3n,

Did you manage to get this to work in the end? I'm trying to do the same.

Thanks.