net: Introduce parse_protocol header_ops callback

Introduce a new optional header_ops callback called parse_protocol and a
wrapper function dev_parse_header_protocol, similar to dev_parse_header.

The new callback's purpose is to extract the protocol number from the L2
header, the format of which is known to the driver, but not to the upper
layers of the stack.

Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index aab4d9f6613dc41e8cabcd6be1f427e1ad31a631..6997f62cb6a0729be86c0c1c2e6f6f4e534636f3 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -274,6 +274,7 @@ struct header_ops {
                                const struct net_device *dev,
                                const unsigned char *haddr);
        bool    (*validate)(const char *ll_header, unsigned int len);
+       __be16  (*parse_protocol)(const struct sk_buff *skb);
 };
 
 /* These flag bits are private to the generic network queueing
@@ -2939,6 +2940,15 @@ static inline int dev_parse_header(const struct sk_buff *skb,
        return dev->header_ops->parse(skb, haddr);
 }
 
+static inline __be16 dev_parse_header_protocol(const struct sk_buff *skb)
+{
+       const struct net_device *dev = skb->dev;
+
+       if (!dev->header_ops || !dev->header_ops->parse_protocol)
+               return 0;
+       return dev->header_ops->parse_protocol(skb);
+}
+
 /* ll_header must have at least hard_header_len allocated */
 static inline bool dev_validate_header(const struct net_device *dev,
                                       char *ll_header, int len)