add prefix length from mtpnc to podipinfo & gatewayip (#2828)

* add prefix length from mtpnc to podipinfo & gatewayip

* separate getIpConfig based on OS for HNS prefix changes, add subnet in UTs

* import packages

* refactor middleware into os files after rebase w/ master

* split only the subnet-prefix assign part

* fix lint errors

* add UTs to test the function's behavior for linux vs windows

---------

Signed-off-by: Kshitija Murudi <kmurudi@microsoft.com>
Co-authored-by: paulyufan2 <paulyu01@outlook.com>

cns/middlewares/k8sSwiftV2.go

@@ -221,7 +221,8 @@ func (k *K8sSWIFTv2Middleware) getIPConfig(ctx context.Context, podInfo cns.PodI
 				if prefixSize != prefixLength {
 					return nil, errors.Wrapf(errInvalidMTPNCPrefixLength, "mtpnc primaryIP prefix length is %d", prefixSize)
 				}
-				podIPInfos = append(podIPInfos, cns.PodIpInfo{
+
+				podIPInfo := cns.PodIpInfo{
 					PodIPConfig: cns.IPSubnet{
 						IPAddress:    ip,
 						PrefixLength: uint8(prefixSize),
@@ -230,9 +231,15 @@ func (k *K8sSWIFTv2Middleware) getIPConfig(ctx context.Context, podInfo cns.PodI
 					NICType:           cns.DelegatedVMNIC,
 					SkipDefaultRoutes: false,
 					// InterfaceName is empty for DelegatedVMNIC
-				})
+				}
+				// for windows scenario, it is required to add additional fields with the exact subnetAddressSpace
+				// received from MTPNC, this function assigns them for windows while linux is a no-op
+				err = k.assignSubnetPrefixLengthFields(&podIPInfo, interfaceInfo, ip)
+				if err != nil {
+					return nil, errors.Wrap(err, "failed to parse mtpnc subnetAddressSpace prefix")
+				}
+				podIPInfos = append(podIPInfos, podIPInfo)
 			}
-
 		}
 	}
 

cns/middlewares/k8sSwiftV2_linux.go

@@ -8,6 +8,7 @@ import (
 	"github.com/Azure/azure-container-networking/cns/configuration"
 	"github.com/Azure/azure-container-networking/cns/logger"
 	"github.com/Azure/azure-container-networking/cns/middlewares/utils"
+	"github.com/Azure/azure-container-networking/crd/multitenancy/api/v1alpha1"
 	"github.com/pkg/errors"
 )
 
@@ -95,3 +96,8 @@ func addRoutes(cidrs []string, gatewayIP string) []cns.Route {
 	}
 	return routes
 }
+
+// assignSubnetPrefixLengthFields is a no-op for linux swiftv2 as the default prefix-length is sufficient
+func (k *K8sSWIFTv2Middleware) assignSubnetPrefixLengthFields(_ *cns.PodIpInfo, _ v1alpha1.InterfaceInfo, _ string) error {
+	return nil
+}

cns/middlewares/k8sSwiftV2_linux_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/Azure/azure-container-networking/cns/logger"
 	"github.com/Azure/azure-container-networking/cns/middlewares/mock"
 	"github.com/Azure/azure-container-networking/cns/types"
+	"github.com/Azure/azure-container-networking/crd/multitenancy/api/v1alpha1"
 	"gotest.tools/v3/assert"
 )
 
@@ -455,3 +456,29 @@ func TestGetSWIFTv2IPConfigMultiInterfaceSuccess(t *testing.T) {
 		assert.Equal(t, ipInfo.SkipDefaultRoutes, false)
 	}
 }
+
+func TestAssignSubnetPrefixSuccess(t *testing.T) {
+	middleware := K8sSWIFTv2Middleware{Cli: mock.NewClient()}
+
+	podIPInfo := cns.PodIpInfo{
+		PodIPConfig: cns.IPSubnet{
+			IPAddress:    "20.240.1.242",
+			PrefixLength: 32,
+		},
+		NICType:    cns.DelegatedVMNIC,
+		MacAddress: "12:34:56:78:9a:bc",
+	}
+
+	intInfo := v1alpha1.InterfaceInfo{
+		GatewayIP:          "20.240.1.1",
+		SubnetAddressSpace: "20.240.1.0/16",
+	}
+
+	ipInfo := podIPInfo
+	err := middleware.assignSubnetPrefixLengthFields(&ipInfo, intInfo, ipInfo.PodIPConfig.IPAddress)
+	assert.Equal(t, err, nil)
+	// assert that the function for linux does not modify any fields
+	assert.Equal(t, ipInfo.PodIPConfig.PrefixLength, uint8(32))
+	assert.Equal(t, ipInfo.HostPrimaryIPInfo.Gateway, "")
+	assert.Equal(t, ipInfo.HostPrimaryIPInfo.Subnet, "")
+}

cns/middlewares/k8sSwiftV2_windows.go

@@ -3,6 +3,9 @@ package middlewares
 import (
 	"github.com/Azure/azure-container-networking/cns"
 	"github.com/Azure/azure-container-networking/cns/logger"
+	"github.com/Azure/azure-container-networking/cns/middlewares/utils"
+	"github.com/Azure/azure-container-networking/crd/multitenancy/api/v1alpha1"
+	"github.com/pkg/errors"
 )
 
 // for AKS L1VH, do not set default route on infraNIC to avoid customer pod reaching all infra vnet services
@@ -14,3 +17,28 @@ func (k *K8sSWIFTv2Middleware) setRoutes(podIPInfo *cns.PodIpInfo) error {
 	}
 	return nil
 }
+
+// assignSubnetPrefixLengthFields will assign the subnet-prefix length to some fields of podipinfo
+// this is required for the windows scenario so that HNS programming is successful for pods
+func (k *K8sSWIFTv2Middleware) assignSubnetPrefixLengthFields(podIPInfo *cns.PodIpInfo, interfaceInfo v1alpha1.InterfaceInfo, ip string) error {
+	// Parse MTPNC SubnetAddressSpace to get the subnet prefix length
+	subnet, subnetPrefix, err := utils.ParseIPAndPrefix(interfaceInfo.SubnetAddressSpace)
+	if err != nil {
+		return errors.Wrap(err, "failed to parse mtpnc subnetAddressSpace prefix")
+	}
+	// assign the subnet-prefix length to all fields in podipinfo
+	podIPInfo.PodIPConfig.PrefixLength = uint8(subnetPrefix)
+	podIPInfo.HostPrimaryIPInfo = cns.HostIPInfo{
+		Gateway:   interfaceInfo.GatewayIP,
+		PrimaryIP: ip,
+		Subnet:    interfaceInfo.SubnetAddressSpace,
+	}
+	podIPInfo.NetworkContainerPrimaryIPConfig = cns.IPConfiguration{
+		IPSubnet: cns.IPSubnet{
+			IPAddress:    subnet,
+			PrefixLength: uint8(subnetPrefix),
+		},
+		GatewayIPAddress: interfaceInfo.GatewayIP,
+	}
+	return nil
+}

cns/middlewares/k8sSwiftV2_windows_test.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/Azure/azure-container-networking/cns"
 	"github.com/Azure/azure-container-networking/cns/middlewares/mock"
+	"github.com/Azure/azure-container-networking/crd/multitenancy/api/v1alpha1"
 	"gotest.tools/v3/assert"
 )
 
@@ -39,3 +40,29 @@ func TestSetRoutesSuccess(t *testing.T) {
 		}
 	}
 }
+
+func TestAssignSubnetPrefixSuccess(t *testing.T) {
+	middleware := K8sSWIFTv2Middleware{Cli: mock.NewClient()}
+
+	podIPInfo := cns.PodIpInfo{
+		PodIPConfig: cns.IPSubnet{
+			IPAddress:    "20.240.1.242",
+			PrefixLength: 32,
+		},
+		NICType:    cns.DelegatedVMNIC,
+		MacAddress: "12:34:56:78:9a:bc",
+	}
+
+	intInfo := v1alpha1.InterfaceInfo{
+		GatewayIP:          "20.240.1.1",
+		SubnetAddressSpace: "20.240.1.0/16",
+	}
+
+	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)
+}

cns/middlewares/mock/mockClient.go

@@ -73,6 +73,7 @@ func NewClient() *Client {
 		GatewayIP:       "10.0.0.1",
 		DeviceType:      v1alpha1.DeviceTypeVnetNIC,
 		AccelnetEnabled: false,
+		SubnetAddressSpace: "192.168.0.0/24",
 	}
 	testInterfaceInfos3 := v1alpha1.InterfaceInfo{
 		NCID:            "testncid",
@@ -81,6 +82,7 @@ func NewClient() *Client {
 		GatewayIP:       "10.0.0.1",
 		DeviceType:      v1alpha1.DeviceTypeVnetNIC,
 		AccelnetEnabled: false,
+		SubnetAddressSpace: "192.168.0.0/24",
 	}
 	testInterfaceInfos5 := v1alpha1.InterfaceInfo{
 		NCID:            "testncid",
@@ -89,6 +91,7 @@ func NewClient() *Client {
 		GatewayIP:       "10.0.0.1",
 		DeviceType:      v1alpha1.DeviceTypeInfiniBandNIC,
 		AccelnetEnabled: true,
+		SubnetAddressSpace: "192.168.0.0/24",
 	}
 
 	testMTPNC1 := v1alpha1.MultitenantPodNetworkConfig{
@@ -216,6 +219,7 @@ func (c *Client) SetMTPNCReady() {
 		GatewayIP:       "10.0.0.1",
 		DeviceType:      v1alpha1.DeviceTypeVnetNIC,
 		AccelnetEnabled: false,
+		SubnetAddressSpace: "192.168.0.0/24",
 	}
 
 	testMTPNC1 := v1alpha1.MultitenantPodNetworkConfig{}