mssim: Refactor device construction

This introduces DeviceOption for customizing the properties of a Device.
It does break the API a bit, but the mssim package is generally only
called from unit test code.

mssim/device.go

@@ -20,14 +20,11 @@ const (
 	DefaultPort uint = 2321
 )
 
-func defaultDevice() *Device {
-	return NewLocalDevice(DefaultPort)
-}
-
 var (
 	// DefaultDevice is configured for the simulator, running locally
-	// with the default port for the TPM channel.
-	DefaultDevice *Device = defaultDevice()
+	// with the default port of 2321 for the TPM channel and 2322 for
+	// the platform channel.
+	DefaultDevice *Device = NewDevice()
 
 	netDial = net.Dial
 )
@@ -56,32 +53,23 @@ type Device struct {
 	retryParams transportutil.RetryParams
 }
 
-// NewLocalDevice returns a new device structure for the specified port on the
-// local machine. It is safe to use from multiple goroutines simultaneously. Note
-// that this assumes the supplied port is for the TPM channel, and that the platform
-// channel is on the subsequent port. The default retry parameters have MaxRetries
-// set to 4, InitialBackoff set to 20ms and the BackoffRate set to 2.
-func NewLocalDevice(port uint, opts ...DeviceOption) *Device {
-	return NewDevice("localhost", port, opts...)
-}
-
-// NewDevice returns a new device structure for the specified host and port. It
-// is safe to use from multiple goroutines simultaneously. Note that this assumes
-// the supplied port is for the TPM channel, and that the platform channel is on
-// the subsequent port. The default retry parameters have MaxRetries set to 4,
-// InitialBackoff set to 20ms and the BackoffRate set to 2.
-func NewDevice(host string, port uint, opts ...DeviceOption) *Device {
-	if host == "" {
-		host = "localhost"
-	}
+// NewDevice returns a new device structure. By default, the host is localhost,
+// the TPM channel port set to [DefaultPort], and it assumes that the platform
+// channel port is [DefaultPort] + 1. The default retry parameters have
+// MaxRetries set to 4, InitialBackoff set to 20ms and the BackoffRate set to 2.
+//
+// It can be customized by any of the [DeviceOption]s.
+//
+// The returned device is safe to use from multiple goroutines simultaneously.
+func NewDevice(opts ...DeviceOption) *Device {
 	dev := &Device{
 		tpm: deviceAddr{
-			Host: host,
-			Port: port,
+			Host: "localhost",
+			Port: DefaultPort,
 		},
 		platform: deviceAddr{
-			Host: host,
-			Port: port + 1,
+			Host: "localhost",
+			Port: DefaultPort + 1,
 		},
 		retryParams: transportutil.RetryParams{
 			MaxRetries:     4,
@@ -95,14 +83,40 @@ func NewDevice(host string, port uint, opts ...DeviceOption) *Device {
 	return dev
 }
 
-// WithPlatformPort is used to customize a device if the simulator has a platform
-// channel on a port that isn't the TPM channel port + 1.
+// WithHost is used to customize the host address on which the simulator's
+// TCP ports can be accessed. The default is localhost.
+func WithHost(host string) DeviceOption {
+	return func(d *Device) {
+		d.tpm.Host = host
+		d.platform.Host = host
+	}
+}
+
+// WithPort is used to customize the TCP ports on which the TPM and platform
+// channels for the simulator are accessed. It sets the platform channel port
+// to the TPM channel port + 1.
+func WithPort(port uint) DeviceOption {
+	return func(d *Device) {
+		d.tpm.Port = port
+		d.platform.Port = port + 1
+	}
+}
+
+// WithTPMPort is used to customize the TCP port on which the TPM channel
+// for the simulator is accessed. It doesn't modify the port for the platform
+// channel.
+func WithTPMPort(port uint) DeviceOption {
+	return func(d *Device) {
+		d.tpm.Port = port
+	}
+}
+
+// WithPlatformPort is used to customize the TCP port on which the platform
+// chanel for the simulator is accessed. It doesn't modify the port for the
+// TPM channel
 func WithPlatformPort(port uint) DeviceOption {
 	return func(d *Device) {
-		d.platform = deviceAddr{
-			Host: d.tpm.Host,
-			Port: port,
-		}
+		d.platform.Port = port
 	}
 }
 

mssim/device_test.go

@@ -24,48 +24,48 @@ var (
 )
 
 func (s *deviceSuite) TestNewDevice(c *C) {
-	dev := NewDevice("localhost", 2321)
+	dev := NewDevice()
 	expectedDev := NewMockDevice(&DeviceAddr{Host: "localhost", Port: 2321}, &DeviceAddr{Host: "localhost", Port: 2322}, &defaultRetryParams)
 	c.Check(dev, DeepEquals, expectedDev)
 }
 
 func (s *deviceSuite) TestNewDeviceDifferentHost(c *C) {
-	dev := NewDevice("192.18.1.50", 2321)
+	dev := NewDevice(WithHost("192.18.1.50"))
 	expectedDev := NewMockDevice(&DeviceAddr{Host: "192.18.1.50", Port: 2321}, &DeviceAddr{Host: "192.18.1.50", Port: 2322}, &defaultRetryParams)
 	c.Check(dev, DeepEquals, expectedDev)
 }
 
 func (s *deviceSuite) TestNewDeviceDifferentPort(c *C) {
-	dev := NewDevice("localhost", 4444)
+	dev := NewDevice(WithPort(4444))
 	expectedDev := NewMockDevice(&DeviceAddr{Host: "localhost", Port: 4444}, &DeviceAddr{Host: "localhost", Port: 4445}, &defaultRetryParams)
 	c.Check(dev, DeepEquals, expectedDev)
 }
 
-func (s *deviceSuite) TestNewLocalDevice(c *C) {
-	dev := NewLocalDevice(2321)
-	expectedDev := NewMockDevice(&DeviceAddr{Host: "localhost", Port: 2321}, &DeviceAddr{Host: "localhost", Port: 2322}, &defaultRetryParams)
+func (s *deviceSuite) TestNewDeviceDifferentTPMPort(c *C) {
+	dev := NewDevice(WithTPMPort(4444))
+	expectedDev := NewMockDevice(&DeviceAddr{Host: "localhost", Port: 4444}, &DeviceAddr{Host: "localhost", Port: 2322}, &defaultRetryParams)
 	c.Check(dev, DeepEquals, expectedDev)
 }
 
-func (s *deviceSuite) TestNewLocalDeviceDifferentPort(c *C) {
-	dev := NewLocalDevice(4444)
-	expectedDev := NewMockDevice(&DeviceAddr{Host: "localhost", Port: 4444}, &DeviceAddr{Host: "localhost", Port: 4445}, &defaultRetryParams)
+func (s *deviceSuite) TestNewDeviceDifferentPlatformPort(c *C) {
+	dev := NewDevice(WithPlatformPort(4444))
+	expectedDev := NewMockDevice(&DeviceAddr{Host: "localhost", Port: 2321}, &DeviceAddr{Host: "localhost", Port: 4444}, &defaultRetryParams)
 	c.Check(dev, DeepEquals, expectedDev)
 }
 
-func (s *deviceSuite) TestInfoMethods(c *C) {
-	dev := NewLocalDevice(2321)
-	c.Check(dev.TPMAddr(), DeepEquals, DeviceAddr{Host: "localhost", Port: 2321})
-	c.Check(dev.PlatformAddr(), DeepEquals, DeviceAddr{Host: "localhost", Port: 2322})
-	c.Check(dev.RetryParams(), DeepEquals, defaultRetryParams)
-}
-
-func (s *deviceSuite) TestWithRetryParams(c *C) {
-	dev := NewLocalDevice(2321, WithRetryParams(10, 10*time.Millisecond, 3))
+func (s *deviceSuite) TestNewDeviceWithDifferentRetryParams(c *C) {
+	dev := NewDevice(WithRetryParams(10, 10*time.Millisecond, 3))
 	expectedDev := NewMockDevice(&DeviceAddr{Host: "localhost", Port: 2321}, &DeviceAddr{Host: "localhost", Port: 2322}, &transportutil.RetryParams{
 		MaxRetries:     10,
 		InitialBackoff: 10 * time.Millisecond,
 		BackoffRate:    3,
 	})
 	c.Check(dev, DeepEquals, expectedDev)
 }
+
+func (s *deviceSuite) TestInfoMethods(c *C) {
+	dev := NewDevice()
+	c.Check(dev.TPMAddr(), DeepEquals, DeviceAddr{Host: "localhost", Port: 2321})
+	c.Check(dev.PlatformAddr(), DeepEquals, DeviceAddr{Host: "localhost", Port: 2322})
+	c.Check(dev.RetryParams(), DeepEquals, defaultRetryParams)
+}

mssim/mssim.go

@@ -572,6 +572,6 @@ func (t *tpmMainTransport) Close() error {
 //
 // Deprecated: Use [NewDevice], [NewLocalDevice] or [DefaultDevice].
 func OpenConnection(host string, port uint) (*Transport, error) {
-	device := NewDevice(host, port)
+	device := NewDevice(WithHost(host), WithPort(port))
 	return device.openInternal()
 }

testutil/tpm.go

@@ -169,7 +169,7 @@ var (
 	TPMDevicePath string = "/dev/tpm0"
 
 	// MssimPort defines the port number of the TPM simulator command port where TPMBackend is TPMBackendMssim.
-	MssimPort uint = 2321
+	MssimPort uint = mssim.DefaultPort
 
 	wrapMssimTransport = WrapTransport
 
@@ -266,7 +266,7 @@ func (c *tpmSimulatorLaunchContext) stopAndTerminate() (err error) {
 		c.captureErr("terminate", c.terminateFn(stopOk))
 	}()
 
-	device := mssim.NewLocalDevice(c.port)
+	device := mssim.NewDevice(mssim.WithPort(c.port))
 	tpm, err := tpm2.OpenTPMDevice(device)
 	if err != nil {
 		return fmt.Errorf("cannot open simulator connection for stop: %w", err)
@@ -482,7 +482,7 @@ func (c *tpmSimulatorLaunchContext) launch(opts *TPMSimulatorOptions) error {
 		return fmt.Errorf("cannot start simulator: %w", err)
 	}
 
-	device := mssim.NewLocalDevice(c.port)
+	device := mssim.NewDevice(mssim.WithPort(c.port))
 	var tpm *tpm2.TPMContext
 
 	// Give the simulator 5 seconds to start up
@@ -807,7 +807,7 @@ func newDevice(features TPMFeatureFlags) (tpm2.TPMDevice, error) {
 			}
 		}
 	case TPMBackendMssim:
-		device = mssim.NewLocalDevice(MssimPort)
+		device = mssim.NewDevice(mssim.WithPort(MssimPort))
 	}
 
 	return &tpmDevice{
@@ -1012,7 +1012,7 @@ func WrapSimulatorDevice(device *mssim.Device) tpm2.TPMDevice {
 func NewSimulatorDevice() tpm2.TPMDevice {
 	var device *mssim.Device
 	if TPMBackend == TPMBackendMssim {
-		device = mssim.NewLocalDevice(MssimPort)
+		device = mssim.NewDevice(mssim.WithPort(MssimPort))
 	}
 
 	return &simulatorDevice{device: device}