diff --git a/include/net/netfilter/ipv4/nf_conntrack_ipv4.h b/include/net/netfilter/ipv4/nf_conntrack_ipv4.h
index 7573d52a4346..6c3d12e2949f 100644
--- a/include/net/netfilter/ipv4/nf_conntrack_ipv4.h
+++ b/include/net/netfilter/ipv4/nf_conntrack_ipv4.h
@@ -16,9 +16,9 @@ extern struct nf_conntrack_l4proto nf_conntrack_l4proto_tcp4;
 extern struct nf_conntrack_l4proto nf_conntrack_l4proto_udp4;
 extern struct nf_conntrack_l4proto nf_conntrack_l4proto_icmp;
 
-extern int nf_conntrack_ipv4_compat_init(void);
-extern void nf_conntrack_ipv4_compat_fini(void);
+int nf_conntrack_ipv4_compat_init(void);
+void nf_conntrack_ipv4_compat_fini(void);
 
-extern void need_ipv4_conntrack(void);
+void need_ipv4_conntrack(void);
 
 #endif /*_NF_CONNTRACK_IPV4_H*/
diff --git a/include/net/netfilter/ipv4/nf_defrag_ipv4.h b/include/net/netfilter/ipv4/nf_defrag_ipv4.h
index 6b00ea38546b..f01ef208dff6 100644
--- a/include/net/netfilter/ipv4/nf_defrag_ipv4.h
+++ b/include/net/netfilter/ipv4/nf_defrag_ipv4.h
@@ -1,6 +1,6 @@
 #ifndef _NF_DEFRAG_IPV4_H
 #define _NF_DEFRAG_IPV4_H
 
-extern void nf_defrag_ipv4_enable(void);
+void nf_defrag_ipv4_enable(void);
 
 #endif /* _NF_DEFRAG_IPV4_H */
diff --git a/include/net/netfilter/ipv6/nf_defrag_ipv6.h b/include/net/netfilter/ipv6/nf_defrag_ipv6.h
index fd79c9a1779d..5613412e7dc2 100644
--- a/include/net/netfilter/ipv6/nf_defrag_ipv6.h
+++ b/include/net/netfilter/ipv6/nf_defrag_ipv6.h
@@ -1,15 +1,14 @@
 #ifndef _NF_DEFRAG_IPV6_H
 #define _NF_DEFRAG_IPV6_H
 
-extern void nf_defrag_ipv6_enable(void);
+void nf_defrag_ipv6_enable(void);
 
-extern int nf_ct_frag6_init(void);
-extern void nf_ct_frag6_cleanup(void);
-extern struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb, u32 user);
-extern void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb,
-			       struct net_device *in,
-			       struct net_device *out,
-			       int (*okfn)(struct sk_buff *));
+int nf_ct_frag6_init(void);
+void nf_ct_frag6_cleanup(void);
+struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb, u32 user);
+void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb,
+			struct net_device *in, struct net_device *out,
+			int (*okfn)(struct sk_buff *));
 
 struct inet_frags_ctl;
 
diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index 0c1288a50e8b..01ea6eed1bb1 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -139,15 +139,13 @@ static inline struct net *nf_ct_net(const struct nf_conn *ct)
 }
 
 /* Alter reply tuple (maybe alter helper). */
-extern void
-nf_conntrack_alter_reply(struct nf_conn *ct,
-			 const struct nf_conntrack_tuple *newreply);
+void nf_conntrack_alter_reply(struct nf_conn *ct,
+			      const struct nf_conntrack_tuple *newreply);
 
 /* Is this tuple taken? (ignoring any belonging to the given
    conntrack). */
-extern int
-nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
-			 const struct nf_conn *ignored_conntrack);
+int nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
+			     const struct nf_conn *ignored_conntrack);
 
 /* Return conntrack_info and tuple hash for given skb. */
 static inline struct nf_conn *
@@ -165,37 +163,34 @@ static inline void nf_ct_put(struct nf_conn *ct)
 }
 
 /* Protocol module loading */
-extern int nf_ct_l3proto_try_module_get(unsigned short l3proto);
-extern void nf_ct_l3proto_module_put(unsigned short l3proto);
+int nf_ct_l3proto_try_module_get(unsigned short l3proto);
+void nf_ct_l3proto_module_put(unsigned short l3proto);
 
 /*
  * Allocate a hashtable of hlist_head (if nulls == 0),
  * or hlist_nulls_head (if nulls == 1)
  */
-extern void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
+void *nf_ct_alloc_hashtable(unsigned int *sizep, int nulls);
 
-extern void nf_ct_free_hashtable(void *hash, unsigned int size);
+void nf_ct_free_hashtable(void *hash, unsigned int size);
 
-extern struct nf_conntrack_tuple_hash *
+struct nf_conntrack_tuple_hash *
 __nf_conntrack_find(struct net *net, u16 zone,
 		    const struct nf_conntrack_tuple *tuple);
 
-extern int nf_conntrack_hash_check_insert(struct nf_conn *ct);
+int nf_conntrack_hash_check_insert(struct nf_conn *ct);
 bool nf_ct_delete(struct nf_conn *ct, u32 pid, int report);
 
-extern void nf_conntrack_flush_report(struct net *net, u32 portid, int report);
+void nf_conntrack_flush_report(struct net *net, u32 portid, int report);
 
-extern bool nf_ct_get_tuplepr(const struct sk_buff *skb,
-			      unsigned int nhoff, u_int16_t l3num,
-			      struct nf_conntrack_tuple *tuple);
-extern bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
-				 const struct nf_conntrack_tuple *orig);
+bool nf_ct_get_tuplepr(const struct sk_buff *skb, unsigned int nhoff,
+		       u_int16_t l3num, struct nf_conntrack_tuple *tuple);
+bool nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse,
+			  const struct nf_conntrack_tuple *orig);
 
-extern void __nf_ct_refresh_acct(struct nf_conn *ct,
-				 enum ip_conntrack_info ctinfo,
-				 const struct sk_buff *skb,
-				 unsigned long extra_jiffies,
-				 int do_acct);
+void __nf_ct_refresh_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
+			  const struct sk_buff *skb,
+			  unsigned long extra_jiffies, int do_acct);
 
 /* Refresh conntrack for this many jiffies and do accounting */
 static inline void nf_ct_refresh_acct(struct nf_conn *ct,
@@ -214,10 +209,8 @@ static inline void nf_ct_refresh(struct nf_conn *ct,
 	__nf_ct_refresh_acct(ct, 0, skb, extra_jiffies, 0);
 }
 
-extern bool __nf_ct_kill_acct(struct nf_conn *ct,
-			      enum ip_conntrack_info ctinfo,
-			      const struct sk_buff *skb,
-			      int do_acct);
+bool __nf_ct_kill_acct(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
+		       const struct sk_buff *skb, int do_acct);
 
 /* kill conntrack and do accounting */
 static inline bool nf_ct_kill_acct(struct nf_conn *ct,
@@ -244,19 +237,17 @@ static inline struct nf_conn *nf_ct_untracked_get(void)
 {
 	return &__raw_get_cpu_var(nf_conntrack_untracked);
 }
-extern void nf_ct_untracked_status_or(unsigned long bits);
+void nf_ct_untracked_status_or(unsigned long bits);
 
 /* Iterate over all conntracks: if iter returns true, it's deleted. */
-extern void
-nf_ct_iterate_cleanup(struct net *net,
-		      int (*iter)(struct nf_conn *i, void *data),
-		      void *data, u32 portid, int report);
-extern void nf_conntrack_free(struct nf_conn *ct);
-extern struct nf_conn *
-nf_conntrack_alloc(struct net *net, u16 zone,
-		   const struct nf_conntrack_tuple *orig,
-		   const struct nf_conntrack_tuple *repl,
-		   gfp_t gfp);
+void nf_ct_iterate_cleanup(struct net *net,
+			   int (*iter)(struct nf_conn *i, void *data),
+			   void *data, u32 portid, int report);
+void nf_conntrack_free(struct nf_conn *ct);
+struct nf_conn *nf_conntrack_alloc(struct net *net, u16 zone,
+				   const struct nf_conntrack_tuple *orig,
+				   const struct nf_conntrack_tuple *repl,
+				   gfp_t gfp);
 
 static inline int nf_ct_is_template(const struct nf_conn *ct)
 {
@@ -287,7 +278,7 @@ static inline bool nf_is_loopback_packet(const struct sk_buff *skb)
 
 struct kernel_param;
 
-extern int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);
+int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);
 extern unsigned int nf_conntrack_htable_size;
 extern unsigned int nf_conntrack_max;
 extern unsigned int nf_conntrack_hash_rnd;
diff --git a/include/net/netfilter/nf_conntrack_acct.h b/include/net/netfilter/nf_conntrack_acct.h
index 2bdb7a15fe06..fef44edf49c1 100644
--- a/include/net/netfilter/nf_conntrack_acct.h
+++ b/include/net/netfilter/nf_conntrack_acct.h
@@ -42,8 +42,8 @@ struct nf_conn_counter *nf_ct_acct_ext_add(struct nf_conn *ct, gfp_t gfp)
 	return acct;
 };
 
-extern unsigned int
-seq_print_acct(struct seq_file *s, const struct nf_conn *ct, int dir);
+unsigned int seq_print_acct(struct seq_file *s, const struct nf_conn *ct,
+			    int dir);
 
 /* Check if connection tracking accounting is enabled */
 static inline bool nf_ct_acct_enabled(struct net *net)
@@ -57,9 +57,9 @@ static inline void nf_ct_set_acct(struct net *net, bool enable)
 	net->ct.sysctl_acct = enable;
 }
 
-extern int nf_conntrack_acct_pernet_init(struct net *net);
-extern void nf_conntrack_acct_pernet_fini(struct net *net);
+int nf_conntrack_acct_pernet_init(struct net *net);
+void nf_conntrack_acct_pernet_fini(struct net *net);
 
-extern int nf_conntrack_acct_init(void);
-extern void nf_conntrack_acct_fini(void);
+int nf_conntrack_acct_init(void);
+void nf_conntrack_acct_fini(void);
 #endif /* _NF_CONNTRACK_ACCT_H */
diff --git a/include/net/netfilter/nf_conntrack_core.h b/include/net/netfilter/nf_conntrack_core.h
index fb2b6234e937..15308b8eb5b5 100644
--- a/include/net/netfilter/nf_conntrack_core.h
+++ b/include/net/netfilter/nf_conntrack_core.h
@@ -20,49 +20,42 @@
 /* This header is used to share core functionality between the
    standalone connection tracking module, and the compatibility layer's use
    of connection tracking. */
-extern unsigned int nf_conntrack_in(struct net *net,
-				    u_int8_t pf,
-				    unsigned int hooknum,
-				    struct sk_buff *skb);
+unsigned int nf_conntrack_in(struct net *net, u_int8_t pf, unsigned int hooknum,
+			     struct sk_buff *skb);
 
-extern int nf_conntrack_init_net(struct net *net);
-extern void nf_conntrack_cleanup_net(struct net *net);
-extern void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list);
+int nf_conntrack_init_net(struct net *net);
+void nf_conntrack_cleanup_net(struct net *net);
+void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list);
 
-extern int nf_conntrack_proto_pernet_init(struct net *net);
-extern void nf_conntrack_proto_pernet_fini(struct net *net);
+int nf_conntrack_proto_pernet_init(struct net *net);
+void nf_conntrack_proto_pernet_fini(struct net *net);
 
-extern int nf_conntrack_proto_init(void);
-extern void nf_conntrack_proto_fini(void);
+int nf_conntrack_proto_init(void);
+void nf_conntrack_proto_fini(void);
 
-extern int nf_conntrack_init_start(void);
-extern void nf_conntrack_cleanup_start(void);
+int nf_conntrack_init_start(void);
+void nf_conntrack_cleanup_start(void);
 
-extern void nf_conntrack_init_end(void);
-extern void nf_conntrack_cleanup_end(void);
+void nf_conntrack_init_end(void);
+void nf_conntrack_cleanup_end(void);
 
-extern bool
-nf_ct_get_tuple(const struct sk_buff *skb,
-		unsigned int nhoff,
-		unsigned int dataoff,
-		u_int16_t l3num,
-		u_int8_t protonum,
-		struct nf_conntrack_tuple *tuple,
-		const struct nf_conntrack_l3proto *l3proto,
-		const struct nf_conntrack_l4proto *l4proto);
+bool nf_ct_get_tuple(const struct sk_buff *skb, unsigned int nhoff,
+		     unsigned int dataoff, u_int16_t l3num, u_int8_t protonum,
+		     struct nf_conntrack_tuple *tuple,
+		     const struct nf_conntrack_l3proto *l3proto,
+		     const struct nf_conntrack_l4proto *l4proto);
 
-extern bool
-nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
-		   const struct nf_conntrack_tuple *orig,
-		   const struct nf_conntrack_l3proto *l3proto,
-		   const struct nf_conntrack_l4proto *l4proto);
+bool nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
+			const struct nf_conntrack_tuple *orig,
+			const struct nf_conntrack_l3proto *l3proto,
+			const struct nf_conntrack_l4proto *l4proto);
 
 /* Find a connection corresponding to a tuple. */
-extern struct nf_conntrack_tuple_hash *
+struct nf_conntrack_tuple_hash *
 nf_conntrack_find_get(struct net *net, u16 zone,
 		      const struct nf_conntrack_tuple *tuple);
 
-extern int __nf_conntrack_confirm(struct sk_buff *skb);
+int __nf_conntrack_confirm(struct sk_buff *skb);
 
 /* Confirm a connection: returns NF_DROP if packet must be dropped. */
 static inline int nf_conntrack_confirm(struct sk_buff *skb)
diff --git a/include/net/netfilter/nf_conntrack_ecache.h b/include/net/netfilter/nf_conntrack_ecache.h
index 092dc651689f..0e3d08e4b1d3 100644
--- a/include/net/netfilter/nf_conntrack_ecache.h
+++ b/include/net/netfilter/nf_conntrack_ecache.h
@@ -68,10 +68,12 @@ struct nf_ct_event_notifier {
 	int (*fcn)(unsigned int events, struct nf_ct_event *item);
 };
 
-extern int nf_conntrack_register_notifier(struct net *net, struct nf_ct_event_notifier *nb);
-extern void nf_conntrack_unregister_notifier(struct net *net, struct nf_ct_event_notifier *nb);
+int nf_conntrack_register_notifier(struct net *net,
+				   struct nf_ct_event_notifier *nb);
+void nf_conntrack_unregister_notifier(struct net *net,
+				      struct nf_ct_event_notifier *nb);
 
-extern void nf_ct_deliver_cached_events(struct nf_conn *ct);
+void nf_ct_deliver_cached_events(struct nf_conn *ct);
 
 static inline void
 nf_conntrack_event_cache(enum ip_conntrack_events event, struct nf_conn *ct)
@@ -166,8 +168,10 @@ struct nf_exp_event_notifier {
 	int (*fcn)(unsigned int events, struct nf_exp_event *item);
 };
 
-extern int nf_ct_expect_register_notifier(struct net *net, struct nf_exp_event_notifier *nb);
-extern void nf_ct_expect_unregister_notifier(struct net *net, struct nf_exp_event_notifier *nb);
+int nf_ct_expect_register_notifier(struct net *net,
+				   struct nf_exp_event_notifier *nb);
+void nf_ct_expect_unregister_notifier(struct net *net,
+				      struct nf_exp_event_notifier *nb);
 
 static inline void
 nf_ct_expect_event_report(enum ip_conntrack_expect_events event,
@@ -207,11 +211,11 @@ nf_ct_expect_event(enum ip_conntrack_expect_events event,
 	nf_ct_expect_event_report(event, exp, 0, 0);
 }
 
-extern int nf_conntrack_ecache_pernet_init(struct net *net);
-extern void nf_conntrack_ecache_pernet_fini(struct net *net);
+int nf_conntrack_ecache_pernet_init(struct net *net);
+void nf_conntrack_ecache_pernet_fini(struct net *net);
 
-extern int nf_conntrack_ecache_init(void);
-extern void nf_conntrack_ecache_fini(void);
+int nf_conntrack_ecache_init(void);
+void nf_conntrack_ecache_fini(void);
 #else /* CONFIG_NF_CONNTRACK_EVENTS */
 
 static inline void nf_conntrack_event_cache(enum ip_conntrack_events event,
diff --git a/include/net/netfilter/nf_conntrack_extend.h b/include/net/netfilter/nf_conntrack_extend.h
index 88a1d4060d52..86372ae0ee84 100644
--- a/include/net/netfilter/nf_conntrack_extend.h
+++ b/include/net/netfilter/nf_conntrack_extend.h
@@ -73,7 +73,7 @@ static inline void *__nf_ct_ext_find(const struct nf_conn *ct, u8 id)
 	((id##_TYPE *)__nf_ct_ext_find((ext), (id)))
 
 /* Destroy all relationships */
-extern void __nf_ct_ext_destroy(struct nf_conn *ct);
+void __nf_ct_ext_destroy(struct nf_conn *ct);
 static inline void nf_ct_ext_destroy(struct nf_conn *ct)
 {
 	if (ct->ext)
diff --git a/include/net/netfilter/nf_conntrack_helper.h b/include/net/netfilter/nf_conntrack_helper.h
index 26c4ae5bfbb8..6cf614bc0029 100644
--- a/include/net/netfilter/nf_conntrack_helper.h
+++ b/include/net/netfilter/nf_conntrack_helper.h
@@ -52,21 +52,24 @@ struct nf_conntrack_helper {
 	unsigned int queue_num;		/* For user-space helpers. */
 };
 
-extern struct nf_conntrack_helper *
-__nf_conntrack_helper_find(const char *name, u16 l3num, u8 protonum);
+struct nf_conntrack_helper *__nf_conntrack_helper_find(const char *name,
+						       u16 l3num, u8 protonum);
 
-extern struct nf_conntrack_helper *
-nf_conntrack_helper_try_module_get(const char *name, u16 l3num, u8 protonum);
+struct nf_conntrack_helper *nf_conntrack_helper_try_module_get(const char *name,
+							       u16 l3num,
+							       u8 protonum);
 
-extern int nf_conntrack_helper_register(struct nf_conntrack_helper *);
-extern void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
+int nf_conntrack_helper_register(struct nf_conntrack_helper *);
+void nf_conntrack_helper_unregister(struct nf_conntrack_helper *);
 
-extern struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, struct nf_conntrack_helper *helper, gfp_t gfp);
+struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct,
+					  struct nf_conntrack_helper *helper,
+					  gfp_t gfp);
 
-extern int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
-				     gfp_t flags);
+int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
+			      gfp_t flags);
 
-extern void nf_ct_helper_destroy(struct nf_conn *ct);
+void nf_ct_helper_destroy(struct nf_conn *ct);
 
 static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)
 {
@@ -82,17 +85,16 @@ static inline void *nfct_help_data(const struct nf_conn *ct)
 	return (void *)help->data;
 }
 
-extern int nf_conntrack_helper_pernet_init(struct net *net);
-extern void nf_conntrack_helper_pernet_fini(struct net *net);
+int nf_conntrack_helper_pernet_init(struct net *net);
+void nf_conntrack_helper_pernet_fini(struct net *net);
 
-extern int nf_conntrack_helper_init(void);
-extern void nf_conntrack_helper_fini(void);
+int nf_conntrack_helper_init(void);
+void nf_conntrack_helper_fini(void);
 
-extern int nf_conntrack_broadcast_help(struct sk_buff *skb,
-				       unsigned int protoff,
-				       struct nf_conn *ct,
-				       enum ip_conntrack_info ctinfo,
-				       unsigned int timeout);
+int nf_conntrack_broadcast_help(struct sk_buff *skb, unsigned int protoff,
+				struct nf_conn *ct,
+				enum ip_conntrack_info ctinfo,
+				unsigned int timeout);
 
 struct nf_ct_helper_expectfn {
 	struct list_head head;
diff --git a/include/net/netfilter/nf_conntrack_l3proto.h b/include/net/netfilter/nf_conntrack_l3proto.h
index 3bb89eac3fa1..3efab704b7eb 100644
--- a/include/net/netfilter/nf_conntrack_l3proto.h
+++ b/include/net/netfilter/nf_conntrack_l3proto.h
@@ -77,17 +77,17 @@ struct nf_conntrack_l3proto {
 extern struct nf_conntrack_l3proto __rcu *nf_ct_l3protos[AF_MAX];
 
 /* Protocol pernet registration. */
-extern int nf_ct_l3proto_pernet_register(struct net *net,
-					 struct nf_conntrack_l3proto *proto);
-extern void nf_ct_l3proto_pernet_unregister(struct net *net,
-					    struct nf_conntrack_l3proto *proto);
+int nf_ct_l3proto_pernet_register(struct net *net,
+				  struct nf_conntrack_l3proto *proto);
+void nf_ct_l3proto_pernet_unregister(struct net *net,
+				     struct nf_conntrack_l3proto *proto);
 
 /* Protocol global registration. */
-extern int nf_ct_l3proto_register(struct nf_conntrack_l3proto *proto);
-extern void nf_ct_l3proto_unregister(struct nf_conntrack_l3proto *proto);
+int nf_ct_l3proto_register(struct nf_conntrack_l3proto *proto);
+void nf_ct_l3proto_unregister(struct nf_conntrack_l3proto *proto);
 
-extern struct nf_conntrack_l3proto *nf_ct_l3proto_find_get(u_int16_t l3proto);
-extern void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p);
+struct nf_conntrack_l3proto *nf_ct_l3proto_find_get(u_int16_t l3proto);
+void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p);
 
 /* Existing built-in protocols */
 extern struct nf_conntrack_l3proto nf_conntrack_l3proto_generic;
diff --git a/include/net/netfilter/nf_conntrack_l4proto.h b/include/net/netfilter/nf_conntrack_l4proto.h
index b411d7b17dec..4c8d573830b7 100644
--- a/include/net/netfilter/nf_conntrack_l4proto.h
+++ b/include/net/netfilter/nf_conntrack_l4proto.h
@@ -114,22 +114,22 @@ extern struct nf_conntrack_l4proto nf_conntrack_l4proto_generic;
 
 #define MAX_NF_CT_PROTO 256
 
-extern struct nf_conntrack_l4proto *
-__nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto);
+struct nf_conntrack_l4proto *__nf_ct_l4proto_find(u_int16_t l3proto,
+						  u_int8_t l4proto);
 
-extern struct nf_conntrack_l4proto *
-nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto);
-extern void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p);
+struct nf_conntrack_l4proto *nf_ct_l4proto_find_get(u_int16_t l3proto,
+						    u_int8_t l4proto);
+void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p);
 
 /* Protocol pernet registration. */
-extern int nf_ct_l4proto_pernet_register(struct net *net,
-					 struct nf_conntrack_l4proto *proto);
-extern void nf_ct_l4proto_pernet_unregister(struct net *net,
-					    struct nf_conntrack_l4proto *proto);
+int nf_ct_l4proto_pernet_register(struct net *net,
+				  struct nf_conntrack_l4proto *proto);
+void nf_ct_l4proto_pernet_unregister(struct net *net,
+				     struct nf_conntrack_l4proto *proto);
 
 /* Protocol global registration. */
-extern int nf_ct_l4proto_register(struct nf_conntrack_l4proto *proto);
-extern void nf_ct_l4proto_unregister(struct nf_conntrack_l4proto *proto);
+int nf_ct_l4proto_register(struct nf_conntrack_l4proto *proto);
+void nf_ct_l4proto_unregister(struct nf_conntrack_l4proto *proto);
 
 static inline void nf_ct_kfree_compat_sysctl_table(struct nf_proto_net *pn)
 {
@@ -140,11 +140,11 @@ static inline void nf_ct_kfree_compat_sysctl_table(struct nf_proto_net *pn)
 }
 
 /* Generic netlink helpers */
-extern int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
-				      const struct nf_conntrack_tuple *tuple);
-extern int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
-				      struct nf_conntrack_tuple *t);
-extern int nf_ct_port_nlattr_tuple_size(void);
+int nf_ct_port_tuple_to_nlattr(struct sk_buff *skb,
+			       const struct nf_conntrack_tuple *tuple);
+int nf_ct_port_nlattr_to_tuple(struct nlattr *tb[],
+			       struct nf_conntrack_tuple *t);
+int nf_ct_port_nlattr_tuple_size(void);
 extern const struct nla_policy nf_ct_port_nla_policy[];
 
 #ifdef CONFIG_SYSCTL
diff --git a/include/net/netfilter/nf_conntrack_seqadj.h b/include/net/netfilter/nf_conntrack_seqadj.h
index f6177a5fe0ca..4b3362991a25 100644
--- a/include/net/netfilter/nf_conntrack_seqadj.h
+++ b/include/net/netfilter/nf_conntrack_seqadj.h
@@ -30,22 +30,18 @@ static inline struct nf_conn_seqadj *nfct_seqadj_ext_add(struct nf_conn *ct)
 	return nf_ct_ext_add(ct, NF_CT_EXT_SEQADJ, GFP_ATOMIC);
 }
 
-extern int nf_ct_seqadj_init(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
-			     s32 off);
-extern int nf_ct_seqadj_set(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
-			    __be32 seq, s32 off);
-extern void nf_ct_tcp_seqadj_set(struct sk_buff *skb,
-				 struct nf_conn *ct,
-				 enum ip_conntrack_info ctinfo,
-				 s32 off);
+int nf_ct_seqadj_init(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
+		      s32 off);
+int nf_ct_seqadj_set(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
+		     __be32 seq, s32 off);
+void nf_ct_tcp_seqadj_set(struct sk_buff *skb, struct nf_conn *ct,
+			  enum ip_conntrack_info ctinfo, s32 off);
 
-extern int nf_ct_seq_adjust(struct sk_buff *skb,
-			    struct nf_conn *ct, enum ip_conntrack_info ctinfo,
-			    unsigned int protoff);
-extern s32 nf_ct_seq_offset(const struct nf_conn *ct, enum ip_conntrack_dir,
-			    u32 seq);
+int nf_ct_seq_adjust(struct sk_buff *skb, struct nf_conn *ct,
+		     enum ip_conntrack_info ctinfo, unsigned int protoff);
+s32 nf_ct_seq_offset(const struct nf_conn *ct, enum ip_conntrack_dir, u32 seq);
 
-extern int nf_conntrack_seqadj_init(void);
-extern void nf_conntrack_seqadj_fini(void);
+int nf_conntrack_seqadj_init(void);
+void nf_conntrack_seqadj_fini(void);
 
 #endif /* _NF_CONNTRACK_SEQADJ_H */
diff --git a/include/net/netfilter/nf_conntrack_synproxy.h b/include/net/netfilter/nf_conntrack_synproxy.h
index 806f54a290d6..968186642bb1 100644
--- a/include/net/netfilter/nf_conntrack_synproxy.h
+++ b/include/net/netfilter/nf_conntrack_synproxy.h
@@ -56,22 +56,20 @@ struct synproxy_options {
 
 struct tcphdr;
 struct xt_synproxy_info;
-extern void synproxy_parse_options(const struct sk_buff *skb, unsigned int doff,
-				   const struct tcphdr *th,
-				   struct synproxy_options *opts);
-extern unsigned int synproxy_options_size(const struct synproxy_options *opts);
-extern void synproxy_build_options(struct tcphdr *th,
-				   const struct synproxy_options *opts);
+void synproxy_parse_options(const struct sk_buff *skb, unsigned int doff,
+			    const struct tcphdr *th,
+			    struct synproxy_options *opts);
+unsigned int synproxy_options_size(const struct synproxy_options *opts);
+void synproxy_build_options(struct tcphdr *th,
+			    const struct synproxy_options *opts);
 
-extern void synproxy_init_timestamp_cookie(const struct xt_synproxy_info *info,
-					   struct synproxy_options *opts);
-extern void synproxy_check_timestamp_cookie(struct synproxy_options *opts);
+void synproxy_init_timestamp_cookie(const struct xt_synproxy_info *info,
+				    struct synproxy_options *opts);
+void synproxy_check_timestamp_cookie(struct synproxy_options *opts);
 
-extern unsigned int synproxy_tstamp_adjust(struct sk_buff *skb,
-					   unsigned int protoff,
-					   struct tcphdr *th,
-					   struct nf_conn *ct,
-					   enum ip_conntrack_info ctinfo,
-					   const struct nf_conn_synproxy *synproxy);
+unsigned int synproxy_tstamp_adjust(struct sk_buff *skb, unsigned int protoff,
+				    struct tcphdr *th, struct nf_conn *ct,
+				    enum ip_conntrack_info ctinfo,
+				    const struct nf_conn_synproxy *synproxy);
 
 #endif /* _NF_CONNTRACK_SYNPROXY_H */
diff --git a/include/net/netfilter/nf_conntrack_timeout.h b/include/net/netfilter/nf_conntrack_timeout.h
index d23aceb16d94..62308713dd7f 100644
--- a/include/net/netfilter/nf_conntrack_timeout.h
+++ b/include/net/netfilter/nf_conntrack_timeout.h
@@ -76,8 +76,8 @@ nf_ct_timeout_lookup(struct net *net, struct nf_conn *ct,
 }
 
 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT
-extern int nf_conntrack_timeout_init(void);
-extern void nf_conntrack_timeout_fini(void);
+int nf_conntrack_timeout_init(void);
+void nf_conntrack_timeout_fini(void);
 #else
 static inline int nf_conntrack_timeout_init(void)
 {
diff --git a/include/net/netfilter/nf_conntrack_timestamp.h b/include/net/netfilter/nf_conntrack_timestamp.h
index b00461413efd..300ae2209f25 100644
--- a/include/net/netfilter/nf_conntrack_timestamp.h
+++ b/include/net/netfilter/nf_conntrack_timestamp.h
@@ -48,11 +48,11 @@ static inline void nf_ct_set_tstamp(struct net *net, bool enable)
 }
 
 #ifdef CONFIG_NF_CONNTRACK_TIMESTAMP
-extern int nf_conntrack_tstamp_pernet_init(struct net *net);
-extern void nf_conntrack_tstamp_pernet_fini(struct net *net);
+int nf_conntrack_tstamp_pernet_init(struct net *net);
+void nf_conntrack_tstamp_pernet_fini(struct net *net);
 
-extern int nf_conntrack_tstamp_init(void);
-extern void nf_conntrack_tstamp_fini(void);
+int nf_conntrack_tstamp_init(void);
+void nf_conntrack_tstamp_fini(void);
 #else
 static inline int nf_conntrack_tstamp_pernet_init(struct net *net)
 {
diff --git a/include/net/netfilter/nf_nat.h b/include/net/netfilter/nf_nat.h
index 59a192420053..c29b4e545f87 100644
--- a/include/net/netfilter/nf_nat.h
+++ b/include/net/netfilter/nf_nat.h
@@ -41,13 +41,13 @@ struct nf_conn_nat {
 };
 
 /* Set up the info structure to map into this range. */
-extern unsigned int nf_nat_setup_info(struct nf_conn *ct,
-				      const struct nf_nat_range *range,
-				      enum nf_nat_manip_type maniptype);
+unsigned int nf_nat_setup_info(struct nf_conn *ct,
+			       const struct nf_nat_range *range,
+			       enum nf_nat_manip_type maniptype);
 
 /* Is this tuple already taken? (not by us)*/
-extern int nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
-			     const struct nf_conn *ignored_conntrack);
+int nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
+		      const struct nf_conn *ignored_conntrack);
 
 static inline struct nf_conn_nat *nfct_nat(const struct nf_conn *ct)
 {
diff --git a/include/net/netfilter/nf_nat_core.h b/include/net/netfilter/nf_nat_core.h
index 972e1e47ec79..fbfd1ba4254e 100644
--- a/include/net/netfilter/nf_nat_core.h
+++ b/include/net/netfilter/nf_nat_core.h
@@ -7,12 +7,10 @@
 /* This header used to share core functionality between the standalone
    NAT module, and the compatibility layer's use of NAT for masquerading. */
 
-extern unsigned int nf_nat_packet(struct nf_conn *ct,
-				  enum ip_conntrack_info ctinfo,
-				  unsigned int hooknum,
-				  struct sk_buff *skb);
+unsigned int nf_nat_packet(struct nf_conn *ct, enum ip_conntrack_info ctinfo,
+			   unsigned int hooknum, struct sk_buff *skb);
 
-extern int nf_xfrm_me_harder(struct sk_buff *skb, unsigned int family);
+int nf_xfrm_me_harder(struct sk_buff *skb, unsigned int family);
 
 static inline int nf_nat_initialized(struct nf_conn *ct,
 				     enum nf_nat_manip_type manip)
diff --git a/include/net/netfilter/nf_nat_helper.h b/include/net/netfilter/nf_nat_helper.h
index 404324d1d0c4..01bcc6bfbcc9 100644
--- a/include/net/netfilter/nf_nat_helper.h
+++ b/include/net/netfilter/nf_nat_helper.h
@@ -7,14 +7,11 @@
 struct sk_buff;
 
 /* These return true or false. */
-extern int __nf_nat_mangle_tcp_packet(struct sk_buff *skb,
-				      struct nf_conn *ct,
-				      enum ip_conntrack_info ctinfo,
-				      unsigned int protoff,
-				      unsigned int match_offset,
-				      unsigned int match_len,
-				      const char *rep_buffer,
-				      unsigned int rep_len, bool adjust);
+int __nf_nat_mangle_tcp_packet(struct sk_buff *skb, struct nf_conn *ct,
+			       enum ip_conntrack_info ctinfo,
+			       unsigned int protoff, unsigned int match_offset,
+			       unsigned int match_len, const char *rep_buffer,
+			       unsigned int rep_len, bool adjust);
 
 static inline int nf_nat_mangle_tcp_packet(struct sk_buff *skb,
 					   struct nf_conn *ct,
@@ -30,18 +27,14 @@ static inline int nf_nat_mangle_tcp_packet(struct sk_buff *skb,
 					  rep_buffer, rep_len, true);
 }
 
-extern int nf_nat_mangle_udp_packet(struct sk_buff *skb,
-				    struct nf_conn *ct,
-				    enum ip_conntrack_info ctinfo,
-				    unsigned int protoff,
-				    unsigned int match_offset,
-				    unsigned int match_len,
-				    const char *rep_buffer,
-				    unsigned int rep_len);
+int nf_nat_mangle_udp_packet(struct sk_buff *skb, struct nf_conn *ct,
+			     enum ip_conntrack_info ctinfo,
+			     unsigned int protoff, unsigned int match_offset,
+			     unsigned int match_len, const char *rep_buffer,
+			     unsigned int rep_len);
 
 /* Setup NAT on this expected conntrack so it follows master, but goes
  * to port ct->master->saved_proto. */
-extern void nf_nat_follow_master(struct nf_conn *ct,
-				 struct nf_conntrack_expect *this);
+void nf_nat_follow_master(struct nf_conn *ct, struct nf_conntrack_expect *this);
 
 #endif
diff --git a/include/net/netfilter/nf_nat_l3proto.h b/include/net/netfilter/nf_nat_l3proto.h
index bd3b97e02c82..5a2919b2e09a 100644
--- a/include/net/netfilter/nf_nat_l3proto.h
+++ b/include/net/netfilter/nf_nat_l3proto.h
@@ -35,18 +35,15 @@ struct nf_nat_l3proto {
 				   struct nf_nat_range *range);
 };
 
-extern int nf_nat_l3proto_register(const struct nf_nat_l3proto *);
-extern void nf_nat_l3proto_unregister(const struct nf_nat_l3proto *);
-extern const struct nf_nat_l3proto *__nf_nat_l3proto_find(u8 l3proto);
+int nf_nat_l3proto_register(const struct nf_nat_l3proto *);
+void nf_nat_l3proto_unregister(const struct nf_nat_l3proto *);
+const struct nf_nat_l3proto *__nf_nat_l3proto_find(u8 l3proto);
 
-extern int nf_nat_icmp_reply_translation(struct sk_buff *skb,
-					 struct nf_conn *ct,
-					 enum ip_conntrack_info ctinfo,
-					 unsigned int hooknum);
-extern int nf_nat_icmpv6_reply_translation(struct sk_buff *skb,
-					   struct nf_conn *ct,
-					   enum ip_conntrack_info ctinfo,
-					   unsigned int hooknum,
-					   unsigned int hdrlen);
+int nf_nat_icmp_reply_translation(struct sk_buff *skb, struct nf_conn *ct,
+				  enum ip_conntrack_info ctinfo,
+				  unsigned int hooknum);
+int nf_nat_icmpv6_reply_translation(struct sk_buff *skb, struct nf_conn *ct,
+				    enum ip_conntrack_info ctinfo,
+				    unsigned int hooknum, unsigned int hdrlen);
 
 #endif /* _NF_NAT_L3PROTO_H */
diff --git a/include/net/netfilter/nf_nat_l4proto.h b/include/net/netfilter/nf_nat_l4proto.h
index 24feb68d1bcc..12f4cc841b6e 100644
--- a/include/net/netfilter/nf_nat_l4proto.h
+++ b/include/net/netfilter/nf_nat_l4proto.h
@@ -42,10 +42,11 @@ struct nf_nat_l4proto {
 };
 
 /* Protocol registration. */
-extern int nf_nat_l4proto_register(u8 l3proto, const struct nf_nat_l4proto *l4proto);
-extern void nf_nat_l4proto_unregister(u8 l3proto, const struct nf_nat_l4proto *l4proto);
+int nf_nat_l4proto_register(u8 l3proto, const struct nf_nat_l4proto *l4proto);
+void nf_nat_l4proto_unregister(u8 l3proto,
+			       const struct nf_nat_l4proto *l4proto);
 
-extern const struct nf_nat_l4proto *__nf_nat_l4proto_find(u8 l3proto, u8 l4proto);
+const struct nf_nat_l4proto *__nf_nat_l4proto_find(u8 l3proto, u8 l4proto);
 
 /* Built-in protocols. */
 extern const struct nf_nat_l4proto nf_nat_l4proto_tcp;
@@ -54,19 +55,18 @@ extern const struct nf_nat_l4proto nf_nat_l4proto_icmp;
 extern const struct nf_nat_l4proto nf_nat_l4proto_icmpv6;
 extern const struct nf_nat_l4proto nf_nat_l4proto_unknown;
 
-extern bool nf_nat_l4proto_in_range(const struct nf_conntrack_tuple *tuple,
-				    enum nf_nat_manip_type maniptype,
-				    const union nf_conntrack_man_proto *min,
-				    const union nf_conntrack_man_proto *max);
+bool nf_nat_l4proto_in_range(const struct nf_conntrack_tuple *tuple,
+			     enum nf_nat_manip_type maniptype,
+			     const union nf_conntrack_man_proto *min,
+			     const union nf_conntrack_man_proto *max);
 
-extern void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
-					struct nf_conntrack_tuple *tuple,
-					const struct nf_nat_range *range,
-					enum nf_nat_manip_type maniptype,
-					const struct nf_conn *ct,
-					u16 *rover);
+void nf_nat_l4proto_unique_tuple(const struct nf_nat_l3proto *l3proto,
+				 struct nf_conntrack_tuple *tuple,
+				 const struct nf_nat_range *range,
+				 enum nf_nat_manip_type maniptype,
+				 const struct nf_conn *ct, u16 *rover);
 
-extern int nf_nat_l4proto_nlattr_to_range(struct nlattr *tb[],
-					  struct nf_nat_range *range);
+int nf_nat_l4proto_nlattr_to_range(struct nlattr *tb[],
+				   struct nf_nat_range *range);
 
 #endif /*_NF_NAT_L4PROTO_H*/
diff --git a/include/net/netfilter/nf_queue.h b/include/net/netfilter/nf_queue.h
index aaba4bbcdda0..c1d5b3e34a21 100644
--- a/include/net/netfilter/nf_queue.h
+++ b/include/net/netfilter/nf_queue.h
@@ -28,7 +28,7 @@ struct nf_queue_handler {
 
 void nf_register_queue_handler(const struct nf_queue_handler *qh);
 void nf_unregister_queue_handler(void);
-extern void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict);
+void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict);
 
 bool nf_queue_entry_get_refs(struct nf_queue_entry *entry);
 void nf_queue_entry_release_refs(struct nf_queue_entry *entry);
diff --git a/include/net/netfilter/xt_rateest.h b/include/net/netfilter/xt_rateest.h
index 495c71f66e7e..79f45e19f31e 100644
--- a/include/net/netfilter/xt_rateest.h
+++ b/include/net/netfilter/xt_rateest.h
@@ -16,7 +16,7 @@ struct xt_rateest {
 	struct rcu_head			rcu;
 };
 
-extern struct xt_rateest *xt_rateest_lookup(const char *name);
-extern void xt_rateest_put(struct xt_rateest *est);
+struct xt_rateest *xt_rateest_lookup(const char *name);
+void xt_rateest_put(struct xt_rateest *est);
 
 #endif /* _XT_RATEEST_H */