openvswitch: add ct_clear action

This adds a ct_clear action for clearing conntrack state. ct_clear is
currently implemented in OVS userspace, but is not backed by an action
in the kernel datapath. This is useful for flows that may modify a
packet tuple after a ct lookup has already occurred.

Signed-off-by: Eric Garver <e@erig.me>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 27 insertions, 0 deletions

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index a54a556fcdb5..a551232daf61 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -1203,6 +1203,10 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
                                 return err == -EINPROGRESS ? 0 : err;
                         break;
 
+                case OVS_ACTION_ATTR_CT_CLEAR:
+                        err = ovs_ct_clear(skb, key);
+                        break;
+
                 case OVS_ACTION_ATTR_PUSH_ETH:
                         err = push_eth(skb, key, nla_data(a));
                         break;
diff --git a/net/openvswitch/conntrack.c b/net/openvswitch/conntrack.c
index d558e882ca0c..fe861e2f0deb 100644
--- a/net/openvswitch/conntrack.c
+++ b/net/openvswitch/conntrack.c
@@ -1129,6 +1129,17 @@ int ovs_ct_execute(struct net *net, struct sk_buff *skb,
         return err;
 }
 
+int ovs_ct_clear(struct sk_buff *skb, struct sw_flow_key *key)
+{
+        if (skb_nfct(skb)) {
+                nf_conntrack_put(skb_nfct(skb));
+                nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
+                ovs_ct_fill_key(skb, 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)
 {
diff --git a/net/openvswitch/conntrack.h b/net/openvswitch/conntrack.h
index bc7efd1867ab..399dfdd2c4f9 100644
--- a/net/openvswitch/conntrack.h
+++ b/net/openvswitch/conntrack.h
@@ -30,6 +30,7 @@ int ovs_ct_action_to_attr(const struct ovs_conntrack_info *, struct sk_buff *);
 
 int ovs_ct_execute(struct net *, struct sk_buff *, struct sw_flow_key *,
                    const struct ovs_conntrack_info *);
+int ovs_ct_clear(struct sk_buff *skb, struct sw_flow_key *key);
 
 void ovs_ct_fill_key(const struct sk_buff *skb, struct sw_flow_key *key);
 int ovs_ct_put_key(const struct sw_flow_key *swkey,
@@ -73,6 +74,12 @@ static inline int ovs_ct_execute(struct net *net, struct sk_buff *skb,
         return -ENOTSUPP;
 }
 
+static inline int ovs_ct_clear(struct sk_buff *skb,
+                               struct sw_flow_key *key)
+{
+        return -ENOTSUPP;
+}
+
 static inline void ovs_ct_fill_key(const struct sk_buff *skb,
                                    struct sw_flow_key *key)
 {
diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
index fc0ca9a89b8e..dc0d79092e74 100644
--- a/net/openvswitch/flow_netlink.c
+++ b/net/openvswitch/flow_netlink.c
@@ -76,6 +76,7 @@ static bool actions_may_change_flow(const struct nlattr *actions)
                         break;
 
                 case OVS_ACTION_ATTR_CT:
+                case OVS_ACTION_ATTR_CT_CLEAR:
                 case OVS_ACTION_ATTR_HASH:
                 case OVS_ACTION_ATTR_POP_ETH:
                 case OVS_ACTION_ATTR_POP_MPLS:
@@ -2528,6 +2529,7 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
                         [OVS_ACTION_ATTR_SAMPLE] = (u32)-1,
                         [OVS_ACTION_ATTR_HASH] = sizeof(struct ovs_action_hash),
                         [OVS_ACTION_ATTR_CT] = (u32)-1,
+                        [OVS_ACTION_ATTR_CT_CLEAR] = 0,
                         [OVS_ACTION_ATTR_TRUNC] = sizeof(struct ovs_action_trunc),
                         [OVS_ACTION_ATTR_PUSH_ETH] = sizeof(struct ovs_action_push_eth),
                         [OVS_ACTION_ATTR_POP_ETH] = 0,
@@ -2669,6 +2671,9 @@ static int __ovs_nla_copy_actions(struct net *net, const struct nlattr *attr,
                         skip_copy = true;
                         break;
 
+                case OVS_ACTION_ATTR_CT_CLEAR:
+                        break;
+
                 case OVS_ACTION_ATTR_PUSH_ETH:
                         /* Disallow pushing an Ethernet header if one
                          * is already present */