[PATCH] virtio-network: Clarify VLAN filter table configuration

[Parav Pandit <parav@nvidia.com>]

The filtering behavior of the VLAN filter commands is not very clear as
discussed in thread [1].

Hence, add the command description and device requirements for it.

[1] https://www.mail-archive.com/qemu-devel@nongnu.org/msg912392.html
Fixes: https://github.com/oasis-tcs/virtio-spec/issues/147
Suggested-by: Si-Wei Liu <si-wei.liu@oracle.com>
Signed-off-by: Parav Pandit <parav@nvidia.com>
---
 virtio-network.tex | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/virtio-network.tex b/virtio-network.tex
index b05ce61..e2b28d9 100644
--- a/virtio-network.tex
+++ b/virtio-network.tex
@@ -1210,6 +1210,29 @@ \subsubsection{Control Virtqueue}\label{sec:Device Types / Network Device / Devi
 Both the VIRTIO_NET_CTRL_VLAN_ADD and VIRTIO_NET_CTRL_VLAN_DEL
 command take a little-endian 16-bit VLAN id as the command-specific-data.
 
+VIRTIO_NET_CTRL_VLAN_ADD command adds the specified VLAN to the VLAN
+filtering table.
+
+VIRTIO_NET_CTRL_VLAN_DEL command removes specified VLAN from the VLAN
+filtering table which was previously added using
+VIRTIO_NET_CTRL_VLAN_ADD command.
+
+\devicenormative{\subparagraph}{VLAN Filtering}{Device Types / Network Device / Device Operation / Control Virtqueue / VLAN Filtering}
+
+When VIRTIO_NET_F_CTRL_VLAN is not negotiated, the device accepts all
+VLAN tagged packets which matches  device's filter configuration.
+
+When VIRTIO_NET_F_CTRL_VLAN is negotiated, the device starts with empty
+VLAN filtering table.
+
+When VIRTIO_NET_F_CTRL_VLAN is negotiated, the device accepts all the
+VLAN tagged packets whose VLAN tag is found in the VLAN filtering table;
+device should drop all VLAN tagged packets whose VLAN tag is not found
+in the VLAN filtering table.
+
+When VIRTIO_NET_F_CTRL_VLAN is negotiated, the device accepts all
+untagged packets which matches device's filter configuration.
+
 \subparagraph{Legacy Interface: VLAN Filtering}\label{sec:Device Types / Network Device / Device Operation / Control Virtqueue / VLAN Filtering / Legacy Interface: VLAN Filtering}
 When using the legacy interface, transitional devices and drivers
 MUST format the VLAN id
-- 
2.26.2