This method allows the controlling device (i.e. the bridge) to specify
additional headroom to be allocated for skb head on frame reception.
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
v1 -> v2:
- fixed netdev_get_fwd_headroom()
- added netdev_set_rx_headroom() and netdev_reset_rx_headroom() helpers
---
include/linux/netdevice.h | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index e52077f..8f53674 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1093,6 +1093,12 @@ struct tc_to_netdev {
* This function is used to get egress tunnel information for given skb.
* This is useful for retrieving outer tunnel header parameters while
* sampling packet.
+ * * int (*ndo_set_rx_headroom)(struct net_device *dev, int needed_headroom);
+ * This function is used to specify the headroom that the skb must
+ * consider when allocation skb during packet reception. Setting
+ * appropriate rx headroom value allows avoiding skb head copy on
+ * forward. Setting a negative value reset the rx headroom to the
+ * default value.
*
*/
struct net_device_ops {
@@ -1278,6 +1284,8 @@ struct net_device_ops {
bool proto_down);
int (*ndo_fill_metadata_dst)(struct net_device *dev,
struct sk_buff *skb);
+ void (*ndo_set_rx_headroom)(struct net_device *dev,
+ int needed_headroom);
};
/**
@@ -1315,6 +1323,8 @@ struct net_device_ops {
* @IFF_L3MDEV_SLAVE: device is enslaved to an L3 master device
* @IFF_TEAM: device is a team device
* @IFF_RXFH_CONFIGURED: device has had Rx Flow indirection table configured
+ * @IFF_PHONY_HEADROOM: the headroom value is controlled by an external
+ * entity (i.e. the master device for bridged veth)
*/
enum netdev_priv_flags {
IFF_802_1Q_VLAN = 1<<0,
@@ -1343,6 +1353,7 @@ enum netdev_priv_flags {
IFF_L3MDEV_SLAVE = 1<<23,
IFF_TEAM = 1<<24,
IFF_RXFH_CONFIGURED = 1<<25,
+ IFF_PHONY_HEADROOM = 1<<26,
};
#define IFF_802_1Q_VLAN IFF_802_1Q_VLAN
@@ -1937,6 +1948,26 @@ struct netdev_queue *netdev_pick_tx(struct net_device
*dev,
struct sk_buff *skb,
void *accel_priv);
+/* returns the headroom that the master device needs to take in account
+ * when forwarding to this dev
+ */
+static inline unsigned netdev_get_fwd_headroom(struct net_device *dev)
+{
+ return dev->priv_flags & IFF_PHONY_HEADROOM ? 0 : dev->needed_headroom;
+}
+
+static inline void netdev_set_rx_headroom(struct net_device *dev, int new_hr)
+{
+ if (dev->netdev_ops->ndo_set_rx_headroom)
+ dev->netdev_ops->ndo_set_rx_headroom(dev, new_hr);
+}
+
+/* set the device rx headroom to the dev's default */
+static inline void netdev_reset_rx_headroom(struct net_device *dev)
+{
+ netdev_set_rx_headroom(dev, -1);
+}
+
/*
* Net namespace inlines
*/
--
1.8.3.1
