implement dummy device operation by netlink

pkg/proxy/ipvs/netlink.go

@@ -22,4 +22,8 @@ type NetLinkHandle interface {
 	EnsureAddressBind(address, devName string) (exist bool, err error)
 	// UnbindAddress unbind address from the interface
 	UnbindAddress(address, devName string) error
+	// EnsureDummyDevice checks if dummy device is exist and, if not, create one. If the dummy device is already exist, return true.
+	EnsureDummyDevice(devName string) (exist bool, err error)
+	// DeleteDummyDevice deletes the given dummy device by name.
+	DeleteDummyDevice(devName string) error
 }

pkg/proxy/ipvs/netlink_linux.go

@@ -70,3 +70,27 @@ func (h *netlinkHandle) UnbindAddress(address, devName string) error {
 	}
 	return nil
 }
+
+// EnsureDummyDevice is part of interface
+func (h *netlinkHandle) EnsureDummyDevice(devName string) (bool, error) {
+	_, err := h.LinkByName(devName)
+	if err == nil {
+		// found dummy device
+		return true, nil
+	}
+	dummy := &netlink.Dummy{netlink.LinkAttrs{Name: devName}}
+	return false, h.LinkAdd(dummy)
+}
+
+// DeleteDummyDevice is part of interface.
+func (h *netlinkHandle) DeleteDummyDevice(devName string) error {
+	link, err := h.LinkByName(devName)
+	if err != nil {
+		return fmt.Errorf("error deleting a non-exist dummy device: %s", devName)
+	}
+	dummy, ok := link.(*netlink.Dummy)
+	if !ok {
+		return fmt.Errorf("expect dummy device, got device type: %s", link.Type())
+	}
+	return h.LinkDel(dummy)
+}

pkg/proxy/ipvs/netlink_unsupported.go

@@ -39,3 +39,13 @@ func (h *emptyHandle) EnsureAddressBind(address, devName string) (exist bool, er
 func (h *emptyHandle) UnbindAddress(address, devName string) error {
 	return fmt.Errorf("netlink not supported for this platform")
 }
+
+// EnsureDummyDevice is part of interface
+func (h *emptyHandle) EnsureDummyDevice(devName string) (bool, error) {
+	return false, fmt.Errorf("netlink is not supported in this platform")
+}
+
+// DeleteDummyDevice is part of interface.
+func (h *emptyHandle) DeleteDummyDevice(devName string) error {
+	return fmt.Errorf("netlink is not supported in this platform")
+}

pkg/proxy/ipvs/testing/fake.go

@@ -36,3 +36,13 @@ func (h *FakeNetlinkHandle) EnsureAddressBind(address, devName string) (exist bo
 func (h *FakeNetlinkHandle) UnbindAddress(address, devName string) error {
 	return nil
 }
+
+// EnsureDummyDevice is a mock implementation
+func (h *FakeNetlinkHandle) EnsureDummyDevice(devName string) (bool, error) {
+	return false, nil
+}
+
+// DeleteDummyDevice is a mock implementation
+func (h *FakeNetlinkHandle) DeleteDummyDevice(devName string) error {
+	return nil
+}