RE: [EXT] [PATCH v1 2/7] virtio-net: Add flow filter capabilities read commands

[Satananda Burla <sburla@marvell.com>]

> -----Original Message-----
> From: Parav Pandit <parav@nvidia.com>
> Sent: Monday, October 16, 2023 9:35 AM
> To: Satananda Burla <sburla@marvell.com>; virtio-comment@lists.oasis-
> open.org; mst@redhat.com; cohuck@redhat.com
> Cc: Shahaf Shuler <shahafs@nvidia.com>; si-wei.liu@oracle.com;
> xuanzhuo@linux.alibaba.com; Heng Qi <hengqi@linux.alibaba.com>
> Subject: RE: [EXT] [PATCH v1 2/7] virtio-net: Add flow filter capabilities
> read commands
> 
> 
> 
> > From: Satananda Burla <sburla@marvell.com>
> > Sent: Monday, October 16, 2023 5:10 AM
> >
> > Hi Parav
> >
> > > +For the \field{type} of VIRTIO_NET_FF_ETH_HDR, header fields are
> > > +represented by a bitmap in \field{fields_bmap} are following:
> > > +
> > > +\begin{tabular}{|l|l|l|}
> > > +\hline
> > > +Bit & Name & Description \\
> > > +\hline \hline
> > > +0   & VIRTIO_NET_FF_DST_MAC & Destination MAC address in the packet
> \\
> > > +\hline
> > > +1   & VIRTIO_NET_FF_SRC_MAC & Source MAC address in the packet \\
> > > +\hline
> > > +2   & VIRTIO_NET_FF_ETHER_TYPE & Ether type in the packet \\
> > > +\hline
> > > +\end{tabular}
> > How about vlan ? if a filter selects ETHER_TYPE as vlan (0x8100), How to
> then
> > match the vlanid ? I believe I mentioned this in last series as well.
> 
> I am sorry, I noticed now that I missed this comment in v0.
> For VLAN, we need to add a new filter as FF_ETH_VLAN, that has implicit
> type of 0x8100, and match field, mask to have the value.
> Shall we can do incrementally as new type?
Yes but it is better to at least add the enum for the type now or leave
enough spacing between L2 and L3 types so that we don't have
to add those types later out of order. For instance, in encoding the type
field, we could leave first 4 bits(16 values) for L2 FF types and start 
start L3 FF types from 0x10 and so on. I can foresee similar issues with
L2 MPLS label matching, IPV4 extension headers, IPV6 extension headers etc.

Regards
Satananda