hotunplug, unpluggedPodNic: implemet reverse phase1

The commit includes removal of bridge, tap and dummy nic if they exist.
Follow up commits will take care of the caches files deletion.

Notice:
1. The cleanup is general and not binding specific. Any link created
by whatecer binding should be removed (although we curretnly support only
bridge binding hotunplug).
2. Error removing one of the links doesn't block removal on the others.

Signed-off-by: Alona Paz <alkaplan@redhat.com>

pkg/network/driver/common.go

@@ -71,6 +71,7 @@ type NetworkHandler interface {
 	LinkSetUp(link netlink.Link) error
 	LinkSetName(link netlink.Link, name string) error
 	LinkAdd(link netlink.Link) error
+	LinkDel(link netlink.Link) error
 	LinkSetLearningOff(link netlink.Link) error
 	ParseAddr(s string) (*netlink.Addr, error)
 	LinkSetHardwareAddr(link netlink.Link, hwaddr net.HardwareAddr) error
@@ -127,6 +128,9 @@ func (h *NetworkUtilsHandler) LinkSetName(link netlink.Link, name string) error
 func (h *NetworkUtilsHandler) LinkAdd(link netlink.Link) error {
 	return netlink.LinkAdd(link)
 }
+func (h *NetworkUtilsHandler) LinkDel(link netlink.Link) error {
+	return netlink.LinkDel(link)
+}
 func (h *NetworkUtilsHandler) LinkSetLearningOff(link netlink.Link) error {
 	return netlink.LinkSetLearning(link, false)
 }

pkg/network/setup/configstate.go

@@ -135,7 +135,7 @@ func (c *ConfigState) UnplugNetworks(vmi *v1.VirtualMachineInstance, cleanupFunc
 	if err != nil {
 		return err
 	}
-	// c.DeleteCacheInterfaces()
+	// c.cache.Init()
 	return nil
 }
 

pkg/network/setup/network.go

@@ -120,9 +120,8 @@ func (n *VMNetworkConfigurator) UnplugPodNetworksPhase1(vmi *v1.VirtualMachineIn
 	err := configState.UnplugNetworks(
 		vmi,
 		func(podIfaceName string) error {
-			// TODO clean cache
-			// TODO remove bridge and tap device
-			return nil
+			unpluggedPodNic := unpluggedpodnic{podInterfaceName: podIfaceName, handler: n.handler}
+			return unpluggedPodNic.UnplugPhase1()
 		})
 	if err != nil {
 		return fmt.Errorf("failed unplug pod networks phase1: %w", err)

pkg/network/setup/unpluggedpodnic.go

@@ -0,0 +1,55 @@
+package network
+
+import (
+	"errors"
+	"github.com/vishvananda/netlink"
+	k8serrors "k8s.io/apimachinery/pkg/util/errors"
+	netdriver "kubevirt.io/kubevirt/pkg/network/driver"
+	virtnetlink "kubevirt.io/kubevirt/pkg/network/link"
+)
+
+type unpluggedpodnic struct {
+	podInterfaceName string
+	handler          netdriver.NetworkHandler
+}
+
+func (c unpluggedpodnic) UnplugPhase1() error {
+	var unplugErrors []error
+
+	bridgeName := generateInPodBridgeInterfaceName(c.podInterfaceName)
+	err := c.delLinkIfExists(bridgeName)
+	if err != nil {
+		unplugErrors = append(unplugErrors, err)
+	}
+
+	// remove extra nic
+	dummyIfaceName := virtnetlink.GenerateNewBridgedVmiInterfaceName(c.podInterfaceName)
+	err = c.delLinkIfExists(dummyIfaceName)
+	if err != nil {
+		unplugErrors = append(unplugErrors, err)
+	}
+
+	// remove tap if exists
+	tapDeviceName := virtnetlink.GenerateTapDeviceName(c.podInterfaceName)
+	err = c.delLinkIfExists(tapDeviceName)
+	if err != nil {
+		unplugErrors = append(unplugErrors, err)
+	}
+
+	// clean caches
+	// TODO remove all three cache files
+
+	return k8serrors.NewAggregate(unplugErrors)
+
+}
+
+func (c unpluggedpodnic) delLinkIfExists(linkName string) error {
+	link, err := c.handler.LinkByName(linkName)
+	if err != nil {
+		var linkNotFoundErr netlink.LinkNotFoundError
+		if !errors.As(err, linkNotFoundErr) {
+			return err
+		}
+	}
+	return c.handler.LinkDel(link)
+}