ipv4: add ip_sock_set_tos

Add a helper to directly set the IP_TOS sockopt from kernel space without
going through a fake uaccess.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip.h b/include/net/ip.h
index 5b317c9..2fc52e2 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -765,4 +765,6 @@ static inline bool inetdev_valid_mtu(unsigned int mtu)
 	return likely(mtu >= IPV4_MIN_MTU);
 }
 
+void ip_sock_set_tos(struct sock *sk, int val);
+
 #endif	/* _IP_H */