Merge pull request #48091 from rpothier/kubenet-ipv6

Automatic merge from submit-queue (batch tested with PRs 45467, 48091, 48033, 48498)

Allow Kubenet with ipv6

When running kubenet with IPv6, there is a panic as there
is IPv4 specific code the Event function.
With this change, Event will support IPv4 and IPv6



**What this PR does / why we need it**:
This PR allows kubenet to use IPv6. Currently there is a panic in kubenet_linux.go
as there is IPv4 specific code.

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #48089

**Special notes for your reviewer**:

**Release note**:

```release-note-NONE
```

pkg/kubelet/network/kubenet/kubenet_linux.go

@@ -259,7 +259,7 @@ func (plugin *kubenetNetworkPlugin) Event(name string, details map[string]interf
 	if err == nil {
 		setHairpin := plugin.hairpinMode == componentconfig.HairpinVeth
 		// Set bridge address to first address in IPNet
-		cidr.IP.To4()[3] += 1
+		cidr.IP[len(cidr.IP)-1] += 1
 
 		json := fmt.Sprintf(NET_CONFIG_TEMPLATE, BridgeName, plugin.mtu, network.DefaultInterfaceName, setHairpin, podCIDR, cidr.IP.String())
 		glog.V(2).Infof("CNI network config set to %v", json)

pkg/kubelet/network/kubenet/kubenet_linux_test.go

@@ -232,37 +232,61 @@ func TestGenerateMacAddress(t *testing.T) {
 // TestInvocationWithoutRuntime invokes the plugin without a runtime.
 // This is how kubenet is invoked from the cri.
 func TestTearDownWithoutRuntime(t *testing.T) {
-	fhost := nettest.NewFakeHost(nil)
+	testCases := []struct {
-	fhost.Legacy = false
+		podCIDR         string
-	fhost.Runtime = nil
+		ip              string
-	mockcni := &mock_cni.MockCNI{}
+		expectedGateway string
-
+	}{
-	fexec := &exec.FakeExec{
+		{
-		CommandScript: []exec.FakeCommandAction{},
+			podCIDR:         "10.0.0.1/24",
-		LookPathFunc: func(file string) (string, error) {
+			ip:              "10.0.0.1",
-			return fmt.Sprintf("/fake-bin/%s", file), nil
+			expectedGateway: "10.0.0.1",
+		},
+		{
+			podCIDR:         "2001:beef::1/48",
+			ip:              "2001:beef::1",
+			expectedGateway: "2001:beef::1",
 		},
 	}
+	for _, tc := range testCases {
+		fhost := nettest.NewFakeHost(nil)
+		fhost.Legacy = false
+		fhost.Runtime = nil
+		mockcni := &mock_cni.MockCNI{}
 
-	kubenet := newFakeKubenetPlugin(map[kubecontainer.ContainerID]string{}, fexec, fhost)
+		fexec := &exec.FakeExec{
-	kubenet.cniConfig = mockcni
+			CommandScript: []exec.FakeCommandAction{},
-	kubenet.iptables = ipttest.NewFake()
+			LookPathFunc: func(file string) (string, error) {
+				return fmt.Sprintf("/fake-bin/%s", file), nil
+			},
+		}
 
-	details := make(map[string]interface{})
+		kubenet := newFakeKubenetPlugin(map[kubecontainer.ContainerID]string{}, fexec, fhost)
-	details[network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE_DETAIL_CIDR] = "10.0.0.1/24"
+		kubenet.cniConfig = mockcni
-	kubenet.Event(network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE, details)
+		kubenet.iptables = ipttest.NewFake()
 
-	existingContainerID := kubecontainer.BuildContainerID("docker", "123")
+		details := make(map[string]interface{})
-	kubenet.podIPs[existingContainerID] = "10.0.0.1"
+		details[network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE_DETAIL_CIDR] = tc.podCIDR
+		kubenet.Event(network.NET_PLUGIN_EVENT_POD_CIDR_CHANGE, details)
 
-	mockcni.On("DelNetwork", mock.AnythingOfType("*libcni.NetworkConfig"), mock.AnythingOfType("*libcni.RuntimeConf")).Return(nil)
+		if kubenet.gateway.String() != tc.expectedGateway {
+			t.Errorf("generated gateway: %q, expecting: %q", kubenet.gateway.String(), tc.expectedGateway)
+		}
+		if kubenet.podCidr != tc.podCIDR {
+			t.Errorf("generated podCidr: %q, expecting: %q", kubenet.podCidr, tc.podCIDR)
+		}
+		existingContainerID := kubecontainer.BuildContainerID("docker", "123")
+		kubenet.podIPs[existingContainerID] = tc.ip
 
-	if err := kubenet.TearDownPod("namespace", "name", existingContainerID); err != nil {
+		mockcni.On("DelNetwork", mock.AnythingOfType("*libcni.NetworkConfig"), mock.AnythingOfType("*libcni.RuntimeConf")).Return(nil)
-		t.Fatalf("Unexpected error in TearDownPod: %v", err)
+
+		if err := kubenet.TearDownPod("namespace", "name", existingContainerID); err != nil {
+			t.Fatalf("Unexpected error in TearDownPod: %v", err)
+		}
+		// Assert that the CNI DelNetwork made it through and we didn't crash
+		// without a runtime.
+		mockcni.AssertExpectations(t)
 	}
-	// Assert that the CNI DelNetwork made it through and we didn't crash
-	// without a runtime.
-	mockcni.AssertExpectations(t)
 }
 
 //TODO: add unit test for each implementation of network plugin interface