network, namescheme: Consolidate pod interface names

There is a need to consolidate the pod-interface name scheme of networks
given in the VMI spec, so that they can be approached in consistent way
in different times in the VMI's lifecycle.
Introducing NameScheme that maps network names to
their appropriate network/pod interface name.

Signed-off-by: Ram Lavi <ralavi@redhat.com>

pkg/network/namescheme/BUILD.bazel

@@ -5,6 +5,10 @@ go_library(
     srcs = ["networknamescheme.go"],
     importpath = "kubevirt.io/kubevirt/pkg/network/namescheme",
     visibility = ["//visibility:public"],
+    deps = [
+        "//pkg/network/vmispec:go_default_library",
+        "//staging/src/kubevirt.io/api/core/v1:go_default_library",
+    ],
 )
 
 go_test(
@@ -13,5 +17,11 @@ go_test(
         "networknamescheme_suite_test.go",
         "networknamescheme_test.go",
     ],
-    deps = ["//staging/src/kubevirt.io/client-go/testutils:go_default_library"],
+    deps = [
+        ":go_default_library",
+        "//staging/src/kubevirt.io/api/core/v1:go_default_library",
+        "//staging/src/kubevirt.io/client-go/testutils:go_default_library",
+        "//vendor/github.com/onsi/ginkgo/v2:go_default_library",
+        "//vendor/github.com/onsi/gomega:go_default_library",
+    ],
 )

pkg/network/namescheme/networknamescheme.go

@@ -19,4 +19,38 @@
 
 package namescheme
 
+import (
+	"fmt"
+
+	v1 "kubevirt.io/api/core/v1"
+
+	"kubevirt.io/kubevirt/pkg/network/vmispec"
+)
+
 const PrimaryPodInterfaceName = "eth0"
+
+// CreateNetworkNameScheme iterates over the VMI's Networks, and creates for each a pod interface name.
+// The returned map associates between the network name and the generated pod interface name.
+// Primary network will use "eth0" and the secondary ones will use "net<id>" format, where id is an enumeration
+// from 1 to n.
+func CreateNetworkNameScheme(vmiNetworks []v1.Network) map[string]string {
+	networkNameSchemeMap := mapMultusNonDefaultNetworksToPodInterfaceName(vmiNetworks)
+
+	if multusDefaultNetwork := vmispec.LookUpDefaultNetwork(vmiNetworks); multusDefaultNetwork != nil {
+		networkNameSchemeMap[multusDefaultNetwork.Name] = PrimaryPodInterfaceName
+	}
+
+	return networkNameSchemeMap
+}
+
+func mapMultusNonDefaultNetworksToPodInterfaceName(networks []v1.Network) map[string]string {
+	networkNameSchemeMap := map[string]string{}
+	for i, network := range vmispec.FilterMultusNonDefaultNetworks(networks) {
+		networkNameSchemeMap[network.Name] = secondaryInterfaceName(i + 1)
+	}
+	return networkNameSchemeMap
+}
+
+func secondaryInterfaceName(idx int) string {
+	return fmt.Sprintf("net%d", idx)
+}

pkg/network/namescheme/networknamescheme_test.go

@@ -18,3 +18,73 @@
  */
 
 package namescheme_test
+
+import (
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+
+	virtv1 "kubevirt.io/api/core/v1"
+
+	"kubevirt.io/kubevirt/pkg/network/namescheme"
+)
+
+var _ = Describe("Network Name Scheme", func() {
+	Context("CreateNetworkNameScheme", func() {
+		DescribeTable("should return the expected NetworkNameSchemeMap",
+			func(networkList []virtv1.Network, expectedNetworkNameSchemeMap map[string]string) {
+				podIfacesNameScheme := namescheme.CreateNetworkNameScheme(networkList)
+
+				Expect(podIfacesNameScheme).To(Equal(expectedNetworkNameSchemeMap))
+			},
+			Entry("when network list is nil", nil, map[string]string{}),
+			Entry("when no multus networks exist",
+				[]virtv1.Network{
+					newPodNetwork("default"),
+				},
+				map[string]string{
+					"default": namescheme.PrimaryPodInterfaceName,
+				}),
+			Entry("when default multus networks exist",
+				[]virtv1.Network{
+					createMultusDefaultNetwork("network0", "default/nad0"),
+					createMultusSecondaryNetwork("network1", "default/nad1"),
+					createMultusSecondaryNetwork("network2", "default/nad2"),
+				},
+				map[string]string{
+					"network0": namescheme.PrimaryPodInterfaceName,
+					"network1": "net1",
+					"network2": "net2",
+				}),
+		)
+	})
+})
+
+func createMultusSecondaryNetwork(name, networkName string) virtv1.Network {
+	return createMultusNetwork(name, networkName)
+}
+
+func createMultusDefaultNetwork(name, networkName string) virtv1.Network {
+	multusNetwork := createMultusNetwork(name, networkName)
+	multusNetwork.Multus.Default = true
+	return multusNetwork
+}
+
+func createMultusNetwork(name, networkName string) virtv1.Network {
+	return virtv1.Network{
+		Name: name,
+		NetworkSource: virtv1.NetworkSource{
+			Multus: &virtv1.MultusNetwork{
+				NetworkName: networkName,
+			},
+		},
+	}
+}
+
+func newPodNetwork(name string) virtv1.Network {
+	return virtv1.Network{
+		Name: name,
+		NetworkSource: virtv1.NetworkSource{
+			Pod: &virtv1.PodNetwork{},
+		},
+	}
+}

pkg/network/setup/podnic.go

@@ -103,9 +103,10 @@ func newPodNIC(vmi *v1.VirtualMachineInstance, network *v1.Network, handler netd
 		return nil, fmt.Errorf("no iface matching with network %s", network.Name)
 	}
 
-	podInterfaceName, err := composePodInterfaceName(vmi, network)
-	if err != nil {
-		return nil, err
+	networkNameScheme := namescheme.CreateNetworkNameScheme(vmi.Spec.Networks)
+	podInterfaceName, exists := networkNameScheme[network.Name]
+	if !exists {
+		return nil, fmt.Errorf("pod interface name not found for network %s", network.Name)
 	}
 
 	return &podNIC{
@@ -361,35 +362,6 @@ func generateInPodBridgeInterfaceName(podInterfaceName string) string {
 	return fmt.Sprintf("k6t-%s", podInterfaceName)
 }
 
-func composePodInterfaceName(vmi *v1.VirtualMachineInstance, network *v1.Network) (string, error) {
-	if isSecondaryMultusNetwork(*network) {
-		multusIndex := findMultusIndex(vmi, network)
-		if multusIndex == -1 {
-			return "", fmt.Errorf("Network name %s not found", network.Name)
-		}
-		return fmt.Sprintf("net%d", multusIndex), nil
-	}
-	return namescheme.PrimaryPodInterfaceName, nil
-}
-
-func findMultusIndex(vmi *v1.VirtualMachineInstance, networkToFind *v1.Network) int {
-	idxMultus := 0
-	for _, network := range vmi.Spec.Networks {
-		if isSecondaryMultusNetwork(network) {
-			// multus pod interfaces start from 1
-			idxMultus++
-			if network.Name == networkToFind.Name {
-				return idxMultus
-			}
-		}
-	}
-	return -1
-}
-
-func isSecondaryMultusNetwork(net v1.Network) bool {
-	return net.Multus != nil && !net.Multus.Default
-}
-
 func getPIDString(pid *int) string {
 	if pid != nil {
 		return fmt.Sprintf("%d", *pid)

pkg/network/vmispec/network.go

@@ -34,13 +34,22 @@ func lookupPodNetwork(networks []v1.Network) *v1.Network {
 func FilterMultusNonDefaultNetworks(networks []v1.Network) []v1.Network {
 	var multusNetworks []v1.Network
 	for _, network := range networks {
-		if isSecondaryMultusNetwork(network) {
+		if IsSecondaryMultusNetwork(network) {
 			multusNetworks = append(multusNetworks, network)
 		}
 	}
 	return multusNetworks
 }
 
-func isSecondaryMultusNetwork(net v1.Network) bool {
+func LookUpDefaultNetwork(networks []v1.Network) *v1.Network {
+	for i, network := range networks {
+		if !IsSecondaryMultusNetwork(network) {
+			return &networks[i]
+		}
+	}
+	return nil
+}
+
+func IsSecondaryMultusNetwork(net v1.Network) bool {
 	return net.Multus != nil && !net.Multus.Default
 }

pkg/network/vmispec/network_test.go

@@ -55,6 +55,33 @@ var _ = Describe("Network", func() {
 				multusSecondaryNetwork3,
 			}),
 	)
+
+	DescribeTable("should fail to return the default network", func(inputNetworks []v1.Network) {
+		Expect(vmispec.LookUpDefaultNetwork(inputNetworks)).To(BeNil())
+	},
+		Entry("when there are no networks", []v1.Network{}),
+		Entry("when there are no default networks", []v1.Network{multusSecondaryNetwork1, multusSecondaryNetwork2}),
+	)
+	DescribeTable("should succeed to return the default network", func(inputNetworks []v1.Network, expectNetwork *v1.Network) {
+		Expect(vmispec.LookUpDefaultNetwork(inputNetworks)).To(Equal(expectNetwork))
+	},
+		Entry("when there is a default pod network",
+			[]v1.Network{
+				podNetwork,
+				multusSecondaryNetwork1,
+				multusSecondaryNetwork2,
+			},
+			&podNetwork,
+		),
+		Entry("when there is a multus default network",
+			[]v1.Network{
+				multusDefaultNetwork,
+				multusSecondaryNetwork1,
+				multusSecondaryNetwork2,
+			},
+			&multusDefaultNetwork,
+		),
+	)
 })
 
 func createMultusSecondaryNetwork(name, networkName string) v1.Network {

pkg/virt-controller/services/BUILD.bazel

@@ -15,6 +15,7 @@ go_library(
         "//pkg/hooks:go_default_library",
         "//pkg/host-disk:go_default_library",
         "//pkg/network/istio:go_default_library",
+        "//pkg/network/namescheme:go_default_library",
         "//pkg/network/vmispec:go_default_library",
         "//pkg/util:go_default_library",
         "//pkg/util/hardware:go_default_library",

pkg/virt-controller/services/multus_annotations.go

@@ -25,6 +25,7 @@ import (
 
 	v1 "kubevirt.io/api/core/v1"
 
+	"kubevirt.io/kubevirt/pkg/network/namescheme"
 	"kubevirt.io/kubevirt/pkg/network/vmispec"
 )
 
@@ -58,10 +59,13 @@ func (mnap multusNetworkAnnotationPool) toString() (string, error) {
 func generateMultusCNIAnnotation(vmi *v1.VirtualMachineInstance) (string, error) {
 	multusNetworkAnnotationPool := multusNetworkAnnotationPool{}
 
-	multusNonDefaultNetworks := vmispec.FilterMultusNonDefaultNetworks(vmi.Spec.Networks)
-	for i, network := range multusNonDefaultNetworks {
-		multusNetworkAnnotationPool.add(
-			newMultusAnnotationData(vmi, network, fmt.Sprintf("net%d", i+1)))
+	networkNameScheme := namescheme.CreateNetworkNameScheme(vmi.Spec.Networks)
+	for _, network := range vmi.Spec.Networks {
+		if vmispec.IsSecondaryMultusNetwork(network) {
+			podInterfaceName := networkNameScheme[network.Name]
+			multusNetworkAnnotationPool.add(
+				newMultusAnnotationData(vmi, network, podInterfaceName))
+		}
 	}
 
 	if !multusNetworkAnnotationPool.isEmpty() {