[PATCH v3 4/4] virtio_net: Add support for VLAN filtering in the hypervisor

Alex Williamson
2009-02-01T20:05:25Z

VLAN filtering allows the hypervisor to drop packets from VLANs
that we're not a part of, further reducing the number of extraneous
packets recieved. This makes use of the VLAN virtqueue command class.
The CTRL_VLAN feature bit tells us whether the backend supports VLAN
filtering.

Signed-off-by: Alex Williamson <alex.williamson@hp.com>
---

drivers/net/virtio_net.c | 31 ++++++++++++++++++++++++++++++-
include/linux/virtio_net.h | 13 +++++++++++++
2 files changed, 43 insertions(+), 1 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index e03eebf..d16107b 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -741,6 +741,30 @@ static void virtnet_set_rx_mode(struct net_device *dev)
kfree(buf);
}

+static void virnet_vlan_rx_add_vid(struct net_device *dev, u16 vid)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+ struct scatterlist sg;
+
+ sg_set_buf(&sg, &vid, sizeof(vid));
+
+ if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
+ VIRTIO_NET_CTRL_VLAN_ADD, &sg, 1, 0))
+ dev_warn(&dev->dev, "Failed to add VLAN ID %d.\n", vid);
+}
+
+static void virnet_vlan_rx_kill_vid(struct net_device *dev, u16 vid)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+ struct scatterlist sg;
+
+ sg_set_buf(&sg, &vid, sizeof(vid));
+
+ if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
+ VIRTIO_NET_CTRL_VLAN_DEL, &sg, 1, 0))
+ dev_warn(&dev->dev, "Failed to kill VLAN ID %d.\n", vid);
+}
+
static struct ethtool_ops virtnet_ethtool_ops = {
.set_tx_csum = virtnet_set_tx_csum,
.set_sg = ethtool_op_set_sg,
@@ -767,6 +791,8 @@ static const struct net_device_ops virtnet_netdev = {
.ndo_set_mac_address = virtnet_set_mac_address,
.ndo_set_rx_mode = virtnet_set_rx_mode,
.ndo_change_mtu = virtnet_change_mtu,
+ .ndo_vlan_rx_add_vid = virnet_vlan_rx_add_vid,
+ .ndo_vlan_rx_kill_vid = virnet_vlan_rx_kill_vid,
#ifdef CONFIG_NET_POLL_CONTROLLER
.ndo_poll_controller = virtnet_netpoll,
#endif
@@ -894,6 +920,9 @@ static int virtnet_probe(struct virtio_device *vdev)
err = PTR_ERR(vi->svq);
goto free_send;
}
+
+ if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VLAN))
+ dev->features |= NETIF_F_HW_VLAN_FILTER;
}

/* Initialize our empty receive and send queues. */
@@ -984,7 +1013,7 @@ static unsigned int features[] = {
VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
VIRTIO_NET_F_GUEST_ECN, /* We don't yet handle UFO input. */
VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
- VIRTIO_NET_F_CTRL_RX,
+ VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
VIRTIO_F_NOTIFY_ON_EMPTY,
};

diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 06d9dd6..f22bb39 100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -24,6 +24,7 @@
#define VIRTIO_NET_F_STATUS 16 /* virtio_net_config.status available */
#define VIRTIO_NET_F_CTRL_VQ 17 /* Control channel available */
#define VIRTIO_NET_F_CTRL_RX 18 /* Control channel RX mode support */
+#define VIRTIO_NET_F_CTRL_VLAN 19 /* Control channel VLAN filtering */

#define VIRTIO_NET_S_LINK_UP 1 /* Link is up */

@@ -112,4 +113,16 @@ struct virtio_net_ctrl_mac {
#define VIRTIO_NET_CTRL_MAC 1
#define VIRTIO_NET_CTRL_MAC_TABLE_SET 0

+/*
+ * Control VLAN filtering
+ *
+ * The VLAN filter table is controlled via a simple ADD/DEL interface.
+ * VLAN IDs not added may be filterd by the hypervisor. Del is the
+ * opposite of add. Both commands expect an out entry containing a 2
+ * byte VLAN ID.
+ */
+#define VIRTIO_NET_CTRL_VLAN 2
+ #define VIRTIO_NET_CTRL_VLAN_ADD 0
+ #define VIRTIO_NET_CTRL_VLAN_DEL 1
+
#endif /* _LINUX_VIRTIO_NET_H */