[PATCH net-next 1/2] macvtap: Let TUNSETOFFLOAD actually controll offload features.

[Vlad Yasevich <vyasevic@redhat.com>]

When the user issues TUNSETOFFLOAD ioctl, macvtap does not do
anything other then to verify arguments.  This patch adds
functionality to allow users to actually control offload features.
NETIF_F_GSO and NETIF_F_GRO are always on, but the rest of the
features can be controlled.

Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
---
 drivers/net/macvlan.c      |  9 +++++++++
 drivers/net/macvtap.c      | 41 ++++++++++++++++++++++++++++++++++++++++-
 include/linux/if_macvlan.h |  1 +
 3 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index edfddc5..fa47415 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -638,6 +638,14 @@ static int macvlan_ethtool_get_settings(struct net_device *dev,
 	return __ethtool_get_settings(vlan->lowerdev, cmd);
 }
 
+static netdev_features_t macvlan_fix_features(struct net_device *dev,
+					      netdev_features_t features)
+{
+	struct macvlan_dev *vlan = netdev_priv(dev);
+
+	return (features & vlan->set_features) | (features & ~MACVLAN_FEATURES);
+}
+
 static const struct ethtool_ops macvlan_ethtool_ops = {
 	.get_link		= ethtool_op_get_link,
 	.get_settings		= macvlan_ethtool_get_settings,
@@ -651,6 +659,7 @@ static const struct net_device_ops macvlan_netdev_ops = {
 	.ndo_stop		= macvlan_stop,
 	.ndo_start_xmit		= macvlan_start_xmit,
 	.ndo_change_mtu		= macvlan_change_mtu,
+	.ndo_fix_features	= macvlan_fix_features,
 	.ndo_change_rx_flags	= macvlan_change_rx_flags,
 	.ndo_set_mac_address	= macvlan_set_mac_address,
 	.ndo_set_rx_mode	= macvlan_set_mac_lists,
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 5a76f20..09f0b1f 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -976,6 +976,45 @@ static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags)
 	return ret;
 }
 
+static int set_offload(struct macvtap_queue *q, unsigned long arg)
+{
+	struct macvlan_dev *vlan;
+	netdev_features_t features = NETIF_F_GSO|NETIF_F_GRO;
+	int err = 0;
+
+	if (arg & TUN_F_CSUM) {
+		features = NETIF_F_HW_CSUM;
+
+		if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) {
+			if (arg & TUN_F_TSO_ECN)
+				features |= NETIF_F_TSO_ECN;
+			if (arg & TUN_F_TSO4)
+				features |= NETIF_F_TSO;
+			if (arg & TUN_F_TSO6)
+				features |= NETIF_F_TSO6;
+		}
+
+		if (arg & TUN_F_UFO)
+			features |= NETIF_F_UFO;
+	}
+
+	rtnl_lock();
+	rcu_read_lock_bh();
+	vlan = rcu_dereference_bh(q->vlan);
+	if (!vlan) {
+		err = -ENOLINK;
+		goto unlock;
+	}
+
+	vlan->set_features = features;
+	netdev_update_features(vlan->dev);
+
+unlock:
+	rcu_read_unlock_bh();
+	rtnl_unlock();
+	return err;
+}
+
 /*
  * provide compatibility with generic tun/tap interface
  */
@@ -1062,7 +1101,7 @@ static long macvtap_ioctl(struct file *file, unsigned int cmd,
 			 got enabled for forwarded frames */
 		if (!(q->flags & IFF_VNET_HDR))
 			return  -EINVAL;
-		return 0;
+		return set_offload(q, arg);
 
 	default:
 		return -EINVAL;
diff --git a/include/linux/if_macvlan.h b/include/linux/if_macvlan.h
index f49a9f6..e446e82 100644
--- a/include/linux/if_macvlan.h
+++ b/include/linux/if_macvlan.h
@@ -65,6 +65,7 @@ struct macvlan_dev {
 
 	DECLARE_BITMAP(mc_filter, MACVLAN_MC_FILTER_SZ);
 
+	netdev_features_t	set_features;
 	enum macvlan_mode	mode;
 	u16			flags;
 	int (*receive)(struct sk_buff *skb);
-- 
1.8.1.4