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>

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;