net: move add ct helper function to nf_conntrack_helper for ovs and tc

Move ovs_ct_add_helper from openvswitch to nf_conntrack_helper and
rename as nf_ct_add_helper, so that it can be used in TC act_ct in
the next patch.
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

include/net/netfilter/nf_conntrack_helper.h

@@ -117,6 +117,8 @@ int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
 
 int nf_ct_helper(struct sk_buff *skb, struct nf_conn *ct,
 		 enum ip_conntrack_info ctinfo, u16 proto);
+int nf_ct_add_helper(struct nf_conn *ct, const char *name, u8 family,
+		     u8 proto, bool nat, struct nf_conntrack_helper **hp);
 
 void nf_ct_helper_destroy(struct nf_conn *ct);
 

net/netfilter/nf_conntrack_helper.c

@@ -309,6 +309,37 @@ int nf_ct_helper(struct sk_buff *skb, struct nf_conn *ct,
 }
 EXPORT_SYMBOL_GPL(nf_ct_helper);
 
+int nf_ct_add_helper(struct nf_conn *ct, const char *name, u8 family,
+		     u8 proto, bool nat, struct nf_conntrack_helper **hp)
+{
+	struct nf_conntrack_helper *helper;
+	struct nf_conn_help *help;
+	int ret = 0;
+
+	helper = nf_conntrack_helper_try_module_get(name, family, proto);
+	if (!helper)
+		return -EINVAL;
+
+	help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
+	if (!help) {
+		nf_conntrack_helper_put(helper);
+		return -ENOMEM;
+	}
+#if IS_ENABLED(CONFIG_NF_NAT)
+	if (nat) {
+		ret = nf_nat_helper_try_module_get(name, family, proto);
+		if (ret) {
+			nf_conntrack_helper_put(helper);
+			return ret;
+		}
+	}
+#endif
+	rcu_assign_pointer(help->helper, helper);
+	*hp = helper;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nf_ct_add_helper);
+
 /* appropriate ct lock protecting must be taken by caller */
 static int unhelp(struct nf_conn *ct, void *me)
 {

net/openvswitch/conntrack.c

@@ -1291,43 +1291,6 @@ int ovs_ct_clear(struct sk_buff *skb, struct sw_flow_key *key)
 	return 0;
 }
 
-static int ovs_ct_add_helper(struct ovs_conntrack_info *info, const char *name,
-			     const struct sw_flow_key *key, bool log)
-{
-	struct nf_conntrack_helper *helper;
-	struct nf_conn_help *help;
-	int ret = 0;
-
-	helper = nf_conntrack_helper_try_module_get(name, info->family,
-						    key->ip.proto);
-	if (!helper) {
-		OVS_NLERR(log, "Unknown helper \"%s\"", name);
-		return -EINVAL;
-	}
-
-	help = nf_ct_helper_ext_add(info->ct, GFP_KERNEL);
-	if (!help) {
-		nf_conntrack_helper_put(helper);
-		return -ENOMEM;
-	}
-
-#if IS_ENABLED(CONFIG_NF_NAT)
-	if (info->nat) {
-		ret = nf_nat_helper_try_module_get(name, info->family,
-						   key->ip.proto);
-		if (ret) {
-			nf_conntrack_helper_put(helper);
-			OVS_NLERR(log, "Failed to load \"%s\" NAT helper, error: %d",
-				  name, ret);
-			return ret;
-		}
-	}
-#endif
-	rcu_assign_pointer(help->helper, helper);
-	info->helper = helper;
-	return ret;
-}
-
 #if IS_ENABLED(CONFIG_NF_NAT)
 static int parse_nat(const struct nlattr *attr,
 		     struct ovs_conntrack_info *info, bool log)
@@ -1661,9 +1624,12 @@ int ovs_ct_copy_action(struct net *net, const struct nlattr *attr,
 	}
 
 	if (helper) {
-		err = ovs_ct_add_helper(&ct_info, helper, key, log);
-		if (err)
+		err = nf_ct_add_helper(ct_info.ct, helper, ct_info.family,
+				       key->ip.proto, ct_info.nat, &ct_info.helper);
+		if (err) {
+			OVS_NLERR(log, "Failed to add %s helper %d", helper, err);
 			goto err_free_ct;
+		}
 	}
 
 	err = ovs_nla_add_action(sfa, OVS_ACTION_ATTR_CT, &ct_info,