netfilter: ct_extend: define NF_CT_EXT_* as needed

Less IDs make nf_ct_ext smaller.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

include/net/netfilter/nf_conntrack_ecache.h

@@ -23,12 +23,17 @@ struct nf_conntrack_ecache {
 static inline struct nf_conntrack_ecache *
 nf_ct_ecache_find(const struct nf_conn *ct)
 {
+#ifdef CONFIG_NF_CONNTRACK_EVENTS
 	return nf_ct_ext_find(ct, NF_CT_EXT_ECACHE);
+#else
+	return NULL;
+#endif
 }
 
 static inline struct nf_conntrack_ecache *
 nf_ct_ecache_ext_add(struct nf_conn *ct, u16 ctmask, u16 expmask, gfp_t gfp)
 {
+#ifdef CONFIG_NF_CONNTRACK_EVENTS
 	struct net *net = nf_ct_net(ct);
 	struct nf_conntrack_ecache *e;
 
@@ -45,6 +50,9 @@ nf_ct_ecache_ext_add(struct nf_conn *ct, u16 ctmask, u16 expmask, gfp_t gfp)
 		e->expmask = expmask;
 	}
 	return e;
+#else
+	return NULL;
+#endif
 };
 
 #ifdef CONFIG_NF_CONNTRACK_EVENTS

include/net/netfilter/nf_conntrack_extend.h

@@ -7,10 +7,16 @@
 
 enum nf_ct_ext_id {
 	NF_CT_EXT_HELPER,
+#if defined(CONFIG_NF_NAT) || defined(CONFIG_NF_NAT_MODULE)
 	NF_CT_EXT_NAT,
+#endif
 	NF_CT_EXT_ACCT,
+#ifdef CONFIG_NF_CONNTRACK_EVENTS
 	NF_CT_EXT_ECACHE,
+#endif
+#ifdef CONFIG_NF_CONNTRACK_ZONES
 	NF_CT_EXT_ZONE,
+#endif
 	NF_CT_EXT_NUM,
 };
 

include/net/netfilter/nf_nat.h

@@ -84,7 +84,11 @@ extern int nf_nat_used_tuple(const struct nf_conntrack_tuple *tuple,
 
 static inline struct nf_conn_nat *nfct_nat(const struct nf_conn *ct)
 {
+#if defined(CONFIG_NF_NAT) || defined(CONFIG_NF_NAT_MODULE)
 	return nf_ct_ext_find(ct, NF_CT_EXT_NAT);
+#else
+	return NULL;
+#endif
 }
 
 #else  /* !__KERNEL__: iptables wants this to compile. */