[PATCH v3 2/4] virtio_net: Add a set_rx_mode interface

[Alex Williamson <alex.williamson@hp.com>]

Make use of the RX_MODE control virtqueue class to enable the
set_rx_mode netdev interface.  This allows us to selectively
enable/disable promiscuous and allmulti mode so we don't see
packets we don't want.  For now, we automatically enable these
as needed if additional unicast or multicast addresses are
requested.

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

 drivers/net/virtio_net.c   |   32 ++++++++++++++++++++++++++++++++
 include/linux/virtio_net.h |   13 ++++++++++++-
 2 files changed, 44 insertions(+), 1 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d84e176..f43b9d3 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -672,6 +672,36 @@ static int virtnet_set_tx_csum(struct net_device *dev, u32 data)
 	return ethtool_op_set_tx_hw_csum(dev, data);
 }
 
+static void virtnet_set_rx_mode(struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+	struct scatterlist sg;
+	u8 promisc, allmulti;
+
+	/* 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);
+
+	sg_set_buf(&sg, &promisc, sizeof(promisc));
+
+	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
+				  VIRTIO_NET_CTRL_RX_PROMISC,
+				  &sg, 1, 0))
+		dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
+			 promisc ? "en" : "dis");
+
+	sg_set_buf(&sg, &allmulti, sizeof(allmulti));
+
+	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
+				  VIRTIO_NET_CTRL_RX_ALLMULTI,
+				  &sg, 1, 0))
+		dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
+			 allmulti ? "en" : "dis");
+}
+
 static struct ethtool_ops virtnet_ethtool_ops = {
 	.set_tx_csum = virtnet_set_tx_csum,
 	.set_sg = ethtool_op_set_sg,
@@ -696,6 +726,7 @@ static const struct net_device_ops virtnet_netdev = {
 	.ndo_start_xmit      = start_xmit,
 	.ndo_validate_addr   = eth_validate_addr,
 	.ndo_set_mac_address = virtnet_set_mac_address,
+	.ndo_set_rx_mode     = virtnet_set_rx_mode,
 	.ndo_change_mtu	     = virtnet_change_mtu,
 #ifdef CONFIG_NET_POLL_CONTROLLER
 	.ndo_poll_controller = virtnet_netpoll,
@@ -914,6 +945,7 @@ 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_F_NOTIFY_ON_EMPTY,
 };
 
diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index f28a72a..69569e1 100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -23,6 +23,7 @@
 #define VIRTIO_NET_F_MRG_RXBUF	15	/* Host can merge receive buffers. */
 #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_S_LINK_UP	1	/* Link is up */
 
@@ -76,6 +77,16 @@ typedef __u8 virtio_net_ctrl_ack;
 #define VIRTIO_NET_OK     0
 #define VIRTIO_NET_ERR    1
 
-#define VIRTIO_NET_MAX_CTRL_ARGS   2
+#define VIRTIO_NET_MAX_CTRL_ARGS   3
+
+/*
+ * Control the RX mode, ie. promisucous and allmulti.  PROMISC and
+ * ALLMULTI commands require an "out" sg entry containing a 1 byte
+ * state value, zero = disable, non-zero = enable.  These commands
+ * are supported with the VIRTIO_NET_F_CTRL_RX feature.
+ */
+#define VIRTIO_NET_CTRL_RX    0
+ #define VIRTIO_NET_CTRL_RX_PROMISC      0
+ #define VIRTIO_NET_CTRL_RX_ALLMULTI     1
 
 #endif /* _LINUX_VIRTIO_NET_H */