add default route on delegatedNIC interface

Author: paulyufan2

cns/middlewares/k8sSwiftV2_windows.go

@@ -12,7 +12,14 @@ import (
 // default route is set for secondary interface NIC(i.e,delegatedNIC)
 func (k *K8sSWIFTv2Middleware) setRoutes(podIPInfo *cns.PodIpInfo) error {
 	if podIPInfo.NICType == cns.InfraNIC {
-		logger.Printf("[SWIFTv2Middleware] skip setting default route on InfraNIC interface")
+		// as a workaround, set a default route with gw 0.0.0.0 to avoid HNS setting default route to infraNIC interface
+		// TODO: Remove this once HNS supports custom routes adding to the pod
+		route := cns.Route{
+			IPAddress:        "0.0.0.0/0",
+			GatewayIPAddress: "0.0.0.0",
+		}
+		podIPInfo.Routes = append(podIPInfo.Routes, route)
+
 		podIPInfo.SkipDefaultRoutes = true
 	}
 	return nil
@@ -40,5 +47,12 @@ func (k *K8sSWIFTv2Middleware) assignSubnetPrefixLengthFields(podIPInfo *cns.Pod
 		},
 		GatewayIPAddress: interfaceInfo.GatewayIP,
 	}
+	// assign the default route with gateway IP
+	route := cns.Route {
+		IPAddress: "0.0.0.0/0",
+		GatewayIPAddress: interfaceInfo.GatewayIP,
+	}
+	podIPInfo.Routes = append(podIPInfo.Routes, route)
+
 	return nil
 }

cns/middlewares/k8sSwiftV2_windows_test.go

@@ -1,6 +1,7 @@
 package middlewares
 
 import (
+	"reflect"
 	"testing"
 
 	"github.com/Azure/azure-container-networking/cns"
@@ -53,16 +54,29 @@ func TestAssignSubnetPrefixSuccess(t *testing.T) {
 		MacAddress: "12:34:56:78:9a:bc",
 	}
 
+	gatewayIP := "20.240.1.1"
 	intInfo := v1alpha1.InterfaceInfo{
-		GatewayIP:          "20.240.1.1",
+		GatewayIP:          gatewayIP,
 		SubnetAddressSpace: "20.240.1.0/16",
 	}
 
+	routes := []cns.Route{
+		{
+			IPAddress:        "0.0.0.0/0",
+			GatewayIPAddress: gatewayIP,
+		},
+	}
+
 	ipInfo := podIPInfo
 	err := middleware.assignSubnetPrefixLengthFields(&ipInfo, intInfo, ipInfo.PodIPConfig.IPAddress)
 	assert.Equal(t, err, nil)
 	// assert that the function for windows modifies all the expected fields with prefix-length
 	assert.Equal(t, ipInfo.PodIPConfig.PrefixLength, uint8(16))
 	assert.Equal(t, ipInfo.HostPrimaryIPInfo.Gateway, intInfo.GatewayIP)
 	assert.Equal(t, ipInfo.HostPrimaryIPInfo.Subnet, intInfo.SubnetAddressSpace)
+
+	// compare two slices of routes
+	if !reflect.DeepEqual(ipInfo.Routes, routes) {
+		t.Errorf("got '%+v', expected '%+v'", ipInfo.Routes, routes)
+	}
 }