[ExternalNode] Agent datapath implementation

1. Set up OF pipeline for ExternalNode
2. Install Openflow entries for ExternalNode connectivity
3. Install Openflow entries for ANP on ExternalNode case
4. Supporing installing Openflow entries to bypass traffic to/from
   special peer address on a protocol
5. Unify the flows to process the packets with ct_state match in
   networkpolicy feature between K8s cluster and external node cases

Signed-off-by: wenyingd <[email protected]>

pkg/agent/openflow/pipeline.go

@@ -863,10 +863,14 @@ func (f *featureService) snatConntrackFlows() []binding.Flow {
 // dnsResponseBypassConntrackFlow generates the flow to bypass the dns response packetout from conntrack, to avoid unexpected
 // packet drop. This flow should be installed on the first table of stageConntrackState.
 func (f *featureNetworkPolicy) dnsResponseBypassConntrackFlow(table binding.Table) binding.Flow {
+	nextStage := stageSwitching
+	if f.nodeType == config.ExternalNode {
+		nextStage = stageIngressSecurity
+	}
 	return table.BuildFlow(priorityHigh).
 		MatchRegFieldWithValue(CustomReasonField, CustomReasonDNS).
 		Cookie(f.cookieAllocator.Request(cookie.Default).Raw()).
-		Action().GotoStage(stageSwitching).
+		Action().GotoStage(nextStage).
 		Done()
 }
 

pkg/ovs/ovsconfig/interfaces.go

@@ -35,7 +35,6 @@ type OVSBridgeClient interface {
 	Delete() Error
 	GetExternalIDs() (map[string]string, Error)
 	SetExternalIDs(externalIDs map[string]interface{}) Error
-	GetDatapathID() (string, Error)
 	SetDatapathID(datapathID string) Error
 	GetInterfaceOptions(name string) (map[string]string, Error)
 	SetInterfaceOptions(name string, options map[string]interface{}) Error