Re: [PATCH net-next 0/3] vsock: support network namespace

[Jason Wang]

On Wed, Mar 5, 2025 at 5:30 PM Stefano Garzarella <sgarzare@xxxxxxxxxx> wrote:
>
> On Wed, Mar 05, 2025 at 02:27:12AM -0500, Michael S. Tsirkin wrote:
> >On Tue, Mar 04, 2025 at 04:39:02PM -0800, Bobby Eshleman wrote:
> >> I think it might be a lot of complexity to bring into the picture from
> >> netdev, and I'm not sure there is a big win since the vsock device could
> >> also have a vsock->net itself? I think the complexity will come from the
> >> address translation, which I don't think netdev buys us because there
> >> would still be all of the work work to support vsock in netfilter?
> >
> >Ugh.
> >
> >Guys, let's remember what vsock is.
> >
> >It's a replacement for the serial device with an interface
> >that's easier for userspace to consume, as you get
> >the demultiplexing by the port number.

Interesting, but at least VSOCKETS said:

"""
config VSOCKETS
        tristate "Virtual Socket protocol"
        help
         Virtual Socket Protocol is a socket protocol similar to TCP/IP
          allowing communication between Virtual Machines and hypervisor
          or host.

          You should also select one or more hypervisor-specific transports
          below.

          To compile this driver as a module, choose M here: the module
          will be called vsock. If unsure, say N.
"""

This sounds exactly like networking stuff and spec also said something similar

"""
The virtio socket device is a zero-configuration socket communications
device. It facilitates data transfer between the guest and device
without using the Ethernet or IP protocols.
"""

> >
> >The whole point of vsock is that people do not want
> >any firewalling, filtering, or management on it.

We won't get this, these are for ethernet and TCP/IP mostly.

> >
> >It needs to work with no configuration even if networking is
> >misconfigured or blocked.

I don't see any blockers that prevent us from zero configuration, or I
miss something?

>
> I agree with Michael here.
>
> It's been 5 years and my memory is bad, but using netdev seemed like a
> mess, especially because in vsock we don't have anything related to
> IP/Ethernet/ARP, etc.

We don't need to bother with that, kernel support protocols other than TCP/IP.

>
> I see vsock more as AF_UNIX than netdev.

But you have a device in guest that differs from the AF_UNIX.

>
> I put in CC Jakub who was covering network namespace, maybe he has some
> advice for us regarding this. Context [1].
>
> Thanks,
> Stefano
>
> [1] https://lore.kernel.org/netdev/Z8edJjqAqAaV3Vkt@xxxxxxxxxxxxxxxxxxxxxxxxxxx/
>

Thanks