[PATCH v3 3/4] virtio_net: Add a MAC filter table

Alex Williamson
2009-02-01T20:08:05Z

Make use of the MAC control virtqueue class to support a MAC
filter table. The filter table is managed by the hypervisor.
We consider the table to be available if the CTRL_RX feature
bit is set. We leave it to the hypervisor to manage the table
and enable promiscuous or all-multi mode as necessary depending
on the resources available to it.

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

drivers/net/virtio_net.c | 53 ++++++++++++++++++++++++++++++++++++++------
include/linux/virtio_net.h | 25 ++++++++++++++++++++-
2 files changed, 70 insertions(+), 8 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index f43b9d3..e03eebf 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -675,31 +675,70 @@ static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
static void virtnet_set_rx_mode(struct net_device *dev)
{
struct virtnet_info *vi = netdev_priv(dev);
- struct scatterlist sg;
+ struct scatterlist sg[2];
u8 promisc, allmulti;
+ struct virtio_net_ctrl_mac *mac_data;
+ struct dev_addr_list *addr;
+ void *buf;
+ int i;

/* We can't dynamicaly set ndo_set_rx_mode, so return gracefully */
if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
return;

- promisc = ((dev->flags & IFF_PROMISC) != 0 || dev->uc_count > 0);
- allmulti = ((dev->flags & IFF_ALLMULTI) != 0 || dev->mc_count > 0);
+ promisc = ((dev->flags & IFF_PROMISC) != 0);
+ allmulti = ((dev->flags & IFF_ALLMULTI) != 0);

- sg_set_buf(&sg, &promisc, sizeof(promisc));
+ sg_set_buf(sg, &promisc, sizeof(promisc));

if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
VIRTIO_NET_CTRL_RX_PROMISC,
- &sg, 1, 0))
+ sg, 1, 0))
dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
promisc ? "en" : "dis");

- sg_set_buf(&sg, &allmulti, sizeof(allmulti));
+ sg_set_buf(sg, &allmulti, sizeof(allmulti));

if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
VIRTIO_NET_CTRL_RX_ALLMULTI,
- &sg, 1, 0))
+ sg, 1, 0))
dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
allmulti ? "en" : "dis");
+
+ /* MAC filter - use one buffer for both lists */
+ mac_data = buf = kzalloc(((dev->uc_count + dev->mc_count) * ETH_ALEN) +
+ (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
+ if (!buf) {
+ dev_warn(&dev->dev, "No memory for MAC address buffer\n");
+ return;
+ }
+
+ /* Store the unicast list and count in the front of the buffer */
+ mac_data->entries = dev->uc_count;
+ addr = dev->uc_list;
+ for (i = 0; i < dev->uc_count; i++, addr = addr->next)
+ memcpy(&mac_data->macs[i * ETH_ALEN], addr->da_addr, ETH_ALEN);
+
+ sg_set_buf(&sg[0], mac_data,
+ sizeof(mac_data->entries) + (dev->uc_count * ETH_ALEN));
+
+ /* multicast list and count fill the end */
+ mac_data = (void *)&mac_data->macs[dev->uc_count * ETH_ALEN];
+
+ mac_data->entries = dev->mc_count;
+ addr = dev->mc_list;
+ for (i = 0; i < dev->mc_count; i++, addr = addr->next)
+ memcpy(&mac_data->macs[i * ETH_ALEN], addr->da_addr, ETH_ALEN);
+
+ sg_set_buf(&sg[1], mac_data,
+ sizeof(mac_data->entries) + (dev->mc_count * ETH_ALEN));
+
+ if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
+ VIRTIO_NET_CTRL_MAC_TABLE_SET,
+ sg, 2, 0))
+ dev_warn(&dev->dev, "Failed to set MAC fitler table.\n");
+
+ kfree(buf);
}

static struct ethtool_ops virtnet_ethtool_ops = {
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 69569e1..06d9dd6 100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -77,7 +77,7 @@ typedef __u8 virtio_net_ctrl_ack;
#define VIRTIO_NET_OK 0
#define VIRTIO_NET_ERR 1

-#define VIRTIO_NET_MAX_CTRL_ARGS 3
+#define VIRTIO_NET_MAX_CTRL_ARGS 4

/*
* Control the RX mode, ie. promisucous and allmulti. PROMISC and
@@ -89,4 +89,27 @@ typedef __u8 virtio_net_ctrl_ack;
#define VIRTIO_NET_CTRL_RX_PROMISC 0
#define VIRTIO_NET_CTRL_RX_ALLMULTI 1

+/*
+ * Control the MAC filter table.
+ *
+ * The MAC filter table is managed by the hypervisor, the guest should
+ * assume the size is infinite. Filtering should be considered
+ * non-perfect, ie. based on hypervisor resources, the guest may
+ * received packets from sources not specified in the filter list.
+ *
+ * In addition to the class/cmd header, the TABLE_SET command requires
+ * two out scatterlists. Each contains a 4 byte count of entries followed
+ * by a concatenated byte stream of the ETH_ALEN MAC addresses. The
+ * first sg list contains unicast addresses, the second is for multicast.
+ * This functionality is present if the VIRTIO_NET_F_CTRL_RX feature
+ * is available.
+ */
+struct virtio_net_ctrl_mac {
+ __u32 entries;
+ __u8 macs[];
+} __attribute__((packed));
+
+#define VIRTIO_NET_CTRL_MAC 1
+ #define VIRTIO_NET_CTRL_MAC_TABLE_SET 0
+
#endif /* _LINUX_VIRTIO_NET_H */