diff --git a/include/net/netfilter/nf_conntrack_l4proto.h b/include/net/netfilter/nf_conntrack_l4proto.h
index a120990..ba32ed7 100644
--- a/include/net/netfilter/nf_conntrack_l4proto.h
+++ b/include/net/netfilter/nf_conntrack_l4proto.h
@@ -113,6 +113,7 @@
 				      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);
 extern const struct nla_policy nf_ct_port_nla_policy[];
 
 #ifdef CONFIG_SYSCTL
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index c55bbdc..b182b30 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -921,6 +921,12 @@
 	return 0;
 }
 EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_to_tuple);
+
+int nf_ct_port_nlattr_tuple_size(void)
+{
+	return nla_policy_len(nf_ct_port_nla_policy, CTA_PROTO_MAX + 1);
+}
+EXPORT_SYMBOL_GPL(nf_ct_port_nlattr_tuple_size);
 #endif
 
 /* Used by ipt_REJECT and ip6t_REJECT. */