Revert "openvswitch: switch to per-action label counting in conntrack"

Currently, ovs_ct_set_labels() is only called for confirmed conntrack
entries (ct) within ovs_ct_commit(). However, if the conntrack entry
does not have the labels_ext extension, attempting to allocate it in
ovs_ct_get_conn_labels() for a confirmed entry triggers a warning in
nf_ct_ext_add():

  WARN_ON(nf_ct_is_confirmed(ct));

This happens when the conntrack entry is created externally before OVS
increments net->ct.labels_used. The issue has become more likely since
commit fcb1aa5 ("openvswitch: switch to per-action label counting
in conntrack"), which changed to use per-action label counting and
increment net->ct.labels_used when a flow with ct action is added.

Since there’s no straightforward way to fully resolve this issue at the
moment, this reverts the commit to avoid breaking existing use cases.

Fixes: fcb1aa5 ("openvswitch: switch to per-action label counting in conntrack")
Reported-by: Jianbo Liu <[email protected]>
Signed-off-by: Xin Long <[email protected]>
Acked-by: Aaron Conole <[email protected]>
Link: https://patch.msgid.link/1bdeb2f3a812bca016a225d3de714427b2cd4772.1741457143.git.lucien.xin@gmail.com
Signed-off-by: Paolo Abeni <[email protected]>

Author: lxin

net/openvswitch/conntrack.c

@@ -1368,8 +1368,11 @@ bool ovs_ct_verify(struct net *net, enum ovs_key_attr attr)
 	    attr == OVS_KEY_ATTR_CT_MARK)
 		return true;
 	if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
-	    attr == OVS_KEY_ATTR_CT_LABELS)
-		return true;
+	    attr == OVS_KEY_ATTR_CT_LABELS) {
+		struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
+
+		return ovs_net->xt_label;
+	}
 
 	return false;
 }
@@ -1378,7 +1381,6 @@ int ovs_ct_copy_action(struct net *net, const struct nlattr *attr,
 		       const struct sw_flow_key *key,
 		       struct sw_flow_actions **sfa,  bool log)
 {
-	unsigned int n_bits = sizeof(struct ovs_key_ct_labels) * BITS_PER_BYTE;
 	struct ovs_conntrack_info ct_info;
 	const char *helper = NULL;
 	u16 family;
@@ -1407,12 +1409,6 @@ int ovs_ct_copy_action(struct net *net, const struct nlattr *attr,
 		return -ENOMEM;
 	}
 
-	if (nf_connlabels_get(net, n_bits - 1)) {
-		nf_ct_tmpl_free(ct_info.ct);
-		OVS_NLERR(log, "Failed to set connlabel length");
-		return -EOPNOTSUPP;
-	}
-
 	if (ct_info.timeout[0]) {
 		if (nf_ct_set_timeout(net, ct_info.ct, family, key->ip.proto,
 				      ct_info.timeout))
@@ -1581,7 +1577,6 @@ static void __ovs_ct_free_action(struct ovs_conntrack_info *ct_info)
 	if (ct_info->ct) {
 		if (ct_info->timeout[0])
 			nf_ct_destroy_timeout(ct_info->ct);
-		nf_connlabels_put(nf_ct_net(ct_info->ct));
 		nf_ct_tmpl_free(ct_info->ct);
 	}
 }
@@ -2006,9 +2001,17 @@ struct genl_family dp_ct_limit_genl_family __ro_after_init = {
 
 int ovs_ct_init(struct net *net)
 {
-#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
+	unsigned int n_bits = sizeof(struct ovs_key_ct_labels) * BITS_PER_BYTE;
 	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
 
+	if (nf_connlabels_get(net, n_bits - 1)) {
+		ovs_net->xt_label = false;
+		OVS_NLERR(true, "Failed to set connlabel length");
+	} else {
+		ovs_net->xt_label = true;
+	}
+
+#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
 	return ovs_ct_limit_init(net, ovs_net);
 #else
 	return 0;
@@ -2017,9 +2020,12 @@ int ovs_ct_init(struct net *net)
 
 void ovs_ct_exit(struct net *net)
 {
-#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
 	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
 
+#if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
 	ovs_ct_limit_exit(net, ovs_net);
 #endif
+
+	if (ovs_net->xt_label)
+		nf_connlabels_put(net);
 }

net/openvswitch/datapath.h

@@ -160,6 +160,9 @@ struct ovs_net {
 #if	IS_ENABLED(CONFIG_NETFILTER_CONNCOUNT)
 	struct ovs_ct_limit_info *ct_limit_info;
 #endif
+
+	/* Module reference for configuring conntrack. */
+	bool xt_label;
 };
 
 /**