Re: [RFC PATCH v2 0/5] Add bridge VLAN support

["Oleksii K." <oleksii.kurochko@xxxxxxxxx>]

On Thu, 2024-05-09 at 16:53 +0100, Andrew Cooper wrote:
> On 08/05/2024 10:38 pm, Leigh Brown wrote:
> > Hello all,
> > 
> > I realised over the weekend that there is a valid use case for
> > providing
> > a VIF to a domain that has access to multiple VLANs, e.g. a router.
> > Yes,
> > you can create a VIF per VLAN, but if you start having several
> > VLANs (as
> > I do), it would be nicer to create a single interface that has
> > access to
> > all the relevant VLANs (e.g. enX0.10, enX0.20, etc.).
> > 
> > So, version 2 changes the name and type of the parameter from an
> > integer
> > called `vid' to a string called `vlan'. The vlan parameter is then
> > parsed by the vif-bridge script (actually, the functions called by
> > it in
> > xen-network-common.sh).
> > 
> > As it quite a common practice to allocate VLANs in round numbers, I
> > also
> > implemented the ability to specify contiguous or non-contiguous
> > ranges.
> > You can specify whether a VLAN is tagged or untagged, and which
> > VLAN is
> > the PVID (only one PVID is allowed).  For example,
> > 
> > vif = [ 'mac=xx:xx:xx:xx:xx:xx, bridge=br0, vlan=10p/20-29' ]
> > 
> > will setup the VIF so that 10 is the PVID and VLAN IDs 20 through
> > 29
> > are permitted with tags. Another example:
> > 
> > vif = [ 'mac=xx:xx:xx:xx:xx:xx, bridge=br0, vlan=1p/10+10x9' ]
> > 
> > will setup the bridge to set 1 as the PVID and permit access with
> > tags for VLAN IDs 10, 20, 30, 40, 50, 60, 70, 80 and 90.
> > 
> > This patch set enables this capability as follows:
> > 
> > 1. Adds `vlan' as a new member of the libxl_device_nic structure;
> > 2. Adds support to read and write the vlan parameter from the
> > xenstore;
> > 3. Adds `vlan' as a new keyword for the vif configuration option;
> > 4. Adds support to assign the bridge VLANs in the Linux hotplug
> > scripts;
> > 5. Updated xl-network-configuration(5) manpage and example configs.
> > 
> > Original blurb below:
> > 
> > For many years I have been configuring VLANs on my Linux Dom0 by
> > creating VLAN interfaces for each VLAN I wanted to connect a domain
> > to and then a corresponding bridge. So I would tend to have things
> > like:
> > 
> > enp0s0    -> br0     -> vif1, vif2
> > enp0s0.10 -> br0vl10 -> vif3, vif4
> > enp0s0.20 -> br0vl20 -> vif5
> > dummy0    -> br1     -> vif6
> > 
> > I recently discovered that iproute2 supports creating bridge VLANs
> > that
> > allows you to assign a VLAN to each of the interfaces associated to
> > a
> > bridge. This allows a greatly simplified configuration where a
> > single
> > bridge can support all the domains, and the iproute2 bridge command
> > can
> > assign each VIF to the required VLAN.  This looks like this:
> > 
> > # bridge vlan
> > port              vlan-id  
> > enp0s0            1 PVID Egress Untagged
> >                   10
> >                   20
> > br0               1 PVID Egress Untagged
> > vif1.0            1 PVID Egress Untagged
> > vif2.0            1 PVID Egress Untagged
> > vif3.0            10 PVID Egress Untagged
> > vif4.0            10 PVID Egress Untagged
> > vif5.0            20 PVID Egress Untagged
> > vif6.0            30 PVID Egress Untagged
> > 
> > This patch set enables this capability as follows:
> > 
> > 1. Adds `vid' as a new member of the libxl_device_nic structure;
> > 2. Adds support to read and write vid from the xenstore;
> > 3. Adds `vid' as a new keyword for the vif configuration option;
> > 4. Adds support for assign the bridge VLAN in the Linux hotplug
> > scripts.
> > 
> > I don't believe NetBSD or FreeBSD support this capability, but if
> > they
> > do please point me in the direction of some documentation and/or
> > examples.
> > 
> > NB: I'm not very familiar with Xen code base so may have missed
> > something important, although I have tested it and it is working
> > well
> > for me.
> > 
> > Cheers,
> > 
> > Leigh.
> > 
> > 
> > Leigh Brown (5):
> >   tools/libs/light: Add vlan field to libxl_device_nic
> >   tools/xl: add vlan keyword to vif option
> >   tools/hotplug/Linux: Add bridge VLAN support
> >   docs/man: document VIF vlan keyword
> >   tools/examples: Example Linux bridge VLAN config
> > 
> >  docs/man/xl-network-configuration.5.pod.in    |  38 ++++++
> >  tools/examples/linux-bridge-vlan/README       |  68 +++++++++++
> >  tools/examples/linux-bridge-vlan/br0.netdev   |   7 ++
> >  tools/examples/linux-bridge-vlan/br0.network  |   8 ++
> >  .../examples/linux-bridge-vlan/enp0s0.network |  16 +++
> >  tools/hotplug/Linux/xen-network-common.sh     | 111
> > ++++++++++++++++++
> >  tools/libs/light/libxl_nic.c                  |  10 ++
> >  tools/libs/light/libxl_types.idl              |   1 +
> >  tools/xl/xl_parse.c                           |   2 +
> >  9 files changed, 261 insertions(+)
> >  create mode 100644 tools/examples/linux-bridge-vlan/README
> >  create mode 100644 tools/examples/linux-bridge-vlan/br0.netdev
> >  create mode 100644 tools/examples/linux-bridge-vlan/br0.network
> >  create mode 100644 tools/examples/linux-bridge-vlan/enp0s0.network
> > 
> 
> This is past the last-post date, so Oleksii will need to decide
> whether
> he's happy to make an exception for it.
We also have Feature Freeze this week. But if maintainers think they
have additional/enough time for reviewing this patch series then we can
consider to have in Xen 4.19.

~ Oleksii

> 
> Anthony is OoO for a month now, so if this is to get in for 4.19,
> then
> it will need reviewing by others.  I've CC'd a few plausible
> candidates...
> 
> ~Andrew