}
 
 struct sk_buff;
-extern void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
-                                    __be32 from, __be32 to, int pseudohdr);
-extern void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
-                                     const __be32 *from, const __be32 *to,
-                                     int pseudohdr);
+void inet_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
+                             __be32 from, __be32 to, int pseudohdr);
+void inet_proto_csum_replace16(__sum16 *sum, struct sk_buff *skb,
+                              const __be32 *from, const __be32 *to,
+                              int pseudohdr);
 
 static inline void inet_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
                                            __be16 from, __be16 to,