From: Maxim Mikityanskiy <maximmi@mellanox.com>
Date: Thu, 21 Feb 2019 12:39:58 +0000
Subject: net: Introduce parse_protocol header_ops callback
Patch-mainline: v5.1-rc1
Git-commit: e78b2915517e8fcadb1bc130ad6aeac7099e510c
References: bsc#1176081

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>
Acked-by: Michal Kubecek <mkubecek@suse.cz>

---
 include/linux/netdevice.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -272,6 +272,7 @@ 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
@@ -2725,6 +2726,15 @@ 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)