Create custom BlueZ agent

btsetup.go

@@ -1,27 +1,116 @@
 package infinitime
 
 import (
+	"github.com/godbus/dbus/v5"
 	bt "github.com/muka/go-bluetooth/api"
 	"github.com/muka/go-bluetooth/bluez/profile/adapter"
+	"github.com/muka/go-bluetooth/bluez/profile/agent"
+	"github.com/muka/go-bluetooth/hw/linux/btmgmt"
 )
 
 var defaultAdapter *adapter.Adapter1
+var itdAgent *Agent
 
 func Init() {
+	conn, err := dbus.SystemBus()
+	if err != nil {
+		panic(err)
+	}
+
+	ag := &Agent{}
+	err = agent.ExposeAgent(conn, ag, agent.CapKeyboardDisplay, true)
+	if err != nil {
+		panic(err)
+	}
+
 	// Get bluez default adapter
 	da, err := bt.GetDefaultAdapter()
 	if err != nil {
 		panic(err)
 	}
 
-	da.SetPowered(true)
+	daMgmt := btmgmt.NewBtMgmt(bt.GetDefaultAdapterID())
+	daMgmt.SetPowered(true)
 
 	defaultAdapter = da
+	itdAgent = ag
 }
 
 func Exit() error {
 	if defaultAdapter != nil {
 		defaultAdapter.Close()
 	}
+	agent.RemoveAgent(itdAgent)
 	return bt.Exit()
 }
+
+var errAuthFailed = dbus.NewError("org.bluez.Error.AuthenticationFailed", nil)
+
+// Agent implements the agent.Agent1Client interface.
+// It only requires RequestPasskey as that is all InfiniTime
+// will use.
+type Agent struct {
+	ReqPasskey func() (uint32, error)
+}
+
+// Release returns nil
+func (*Agent) Release() *dbus.Error {
+	return nil
+}
+
+// RequestPinCode returns an empty string and nil
+func (*Agent) RequestPinCode(device dbus.ObjectPath) (pincode string, err *dbus.Error) {
+	return "", nil
+}
+
+// DisplayPinCode returns nil
+func (*Agent) DisplayPinCode(device dbus.ObjectPath, pincode string) *dbus.Error {
+	return nil
+}
+
+// RequestPasskey runs Agent.ReqPasskey and returns the result
+func (a *Agent) RequestPasskey(device dbus.ObjectPath) (uint32, *dbus.Error) {
+	if a.ReqPasskey == nil {
+		return 0, errAuthFailed
+	}
+	passkey, err := a.ReqPasskey()
+	if err != nil {
+		return 0, errAuthFailed
+	}
+	return passkey, nil
+}
+
+// DisplayPasskey returns nil
+func (*Agent) DisplayPasskey(device dbus.ObjectPath, passkey uint32, entered uint16) *dbus.Error {
+	return nil
+}
+
+// RequestConfirmation returns nil
+func (*Agent) RequestConfirmation(device dbus.ObjectPath, passkey uint32) *dbus.Error {
+	return nil
+}
+
+// RequestAuthorization returns nil
+func (*Agent) RequestAuthorization(device dbus.ObjectPath) *dbus.Error {
+	return nil
+}
+
+// AuthorizeService returns nil
+func (*Agent) AuthorizeService(device dbus.ObjectPath, uuid string) *dbus.Error {
+	return nil
+}
+
+// Cancel returns nil
+func (*Agent) Cancel() *dbus.Error {
+	return nil
+}
+
+// Path returns "/dev/arsenm/infinitime/Agent"
+func (*Agent) Path() dbus.ObjectPath {
+	return "/dev/arsenm/infinitime/Agent"
+}
+
+// Interface returns "org.bluez.Agent1"
+func (*Agent) Interface() string {
+	return "org.bluez.Agent1"
+}

infinitime.go

@@ -59,12 +59,14 @@ var (
 	ErrNotConnected     = errors.New("not connected")
 	ErrCharNotAvail     = errors.New("required characteristic is not available")
 	ErrNoTimelineHeader = errors.New("events must contain the timeline header")
+	ErrPairTimeout      = errors.New("reached timeout while pairing")
 )
 
 type Options struct {
 	AttemptReconnect bool
 	WhitelistEnabled bool
 	Whitelist        []string
+	OnReqPasskey     func() (uint32, error)
 }
 
 var DefaultOptions = &Options{
@@ -94,6 +96,8 @@ func Connect(opts *Options) (*Device, error) {
 	}
 	dev.opts = opts
 	dev.onReconnect = func() {}
+	setOnPasskeyReq(opts.OnReqPasskey)
+
 	// Watch device properties
 	devEvtCh, err := dev.device.WatchProperties()
 	if err != nil {
@@ -121,14 +125,29 @@ func Connect(opts *Options) (*Device, error) {
 					dev.device.Properties.Connected = false
 					// While not connected
 					for !dev.device.Properties.Connected {
+						reConnDev := dev
+
+						paired, err := reConnDev.device.GetPaired()
+						if err != nil {
+							continue
+						}
+
+						if !paired {
+							err = reConnDev.pairTimeout()
+							if err != nil {
+								continue
+							}
+						} else {
 							// Attempt to connect via bluetooth address
-						reConnDev, err := ConnectByAddress(dev.device.Properties.Address)
+							reConnDev, err = connectByName(opts)
 							if err != nil {
 								// Decrement disconnect event number
 								disconnEvtNum--
 								// Skip rest of loop
 								continue
 							}
+						}
+
 						// Store onReconn callback
 						onReconn := dev.onReconnect
 						// Set device to new device
@@ -154,6 +173,7 @@ func (i *Device) OnReconnect(f func()) {
 
 // Connect connects to a paired InfiniTime device
 func connectByName(opts *Options) (*Device, error) {
+	setOnPasskeyReq(opts.OnReqPasskey)
 	// Create new device
 	out := &Device{}
 	// Get devices from default adapter
@@ -203,6 +223,7 @@ func contains(ss []string, s string) bool {
 
 // Pair attempts to discover and pair an InfiniTime device
 func pair(opts *Options) (*Device, error) {
+	setOnPasskeyReq(opts.OnReqPasskey)
 	// Create new device
 	out := &Device{}
 	// Start bluetooth discovery
@@ -237,10 +258,17 @@ func pair(opts *Options) (*Device, error) {
 		return nil, ErrNotFound
 	}
 
-	// Pair device
-	out.device.Pair()
+	// Connect to device
+	err = out.device.Connect()
+	if err != nil {
+		return nil, err
+	}
 
-	out.device.Properties.Connected = true
+	// Pair device
+	err = out.pairTimeout()
+	if err != nil {
+		return nil, err
+	}
 
 	// Set connected to true
 	out.device.Properties.Connected = true
@@ -254,32 +282,33 @@ func pair(opts *Options) (*Device, error) {
 	return out, nil
 }
 
-// ConnectByAddress tries to connect to an InifiniTime at
-// the specified InfiniTime address
-func ConnectByAddress(addr string) (*Device, error) {
-	var err error
-	// Create new device
-	out := &Device{}
-	// Get device from bluetooth address
-	out.device, err = defaultAdapter.GetDeviceByAddress(addr)
-	if err != nil {
-		return nil, err
+// setOnPasskeyReq sets the callback for a passkey request.
+// It ensures the function will never be nil.
+func setOnPasskeyReq(onReqPasskey func() (uint32, error)) {
+	itdAgent.ReqPasskey = onReqPasskey
+	if itdAgent.ReqPasskey == nil {
+		itdAgent.ReqPasskey = func() (uint32, error) {
+			return 0, nil
 		}
-
-	// Connect to device
-	err = out.device.Connect()
-	if err != nil {
-		return nil, err
 	}
+}
 
-	out.device.Properties.Connected = true
-
-	// Resolve characteristics
-	err = out.resolveChars()
-	if err != nil {
-		return nil, err
+// pairTimeout tries to pair with the device.
+// It will time out after 20 seconds.
+func (i *Device) pairTimeout() error {
+	errCh := make(chan error)
+	go func() {
+		errCh <- i.device.Pair()
+	}()
+	select {
+	case err := <-errCh:
+		return err
+	case <-time.After(20 * time.Second):
+		if err := i.device.CancelPairing(); err != nil {
+			return err
+		}
+		return ErrPairTimeout
 	}
-	return out, nil
 }
 
 // resolveChars attempts to set all required
@@ -719,7 +748,11 @@ func (i *Device) AddWeatherEvent(event interface{}) error {
 }
 
 func (i *Device) checkStatus(char *gatt.GattCharacteristic1) error {
-	if !i.device.Properties.Connected {
+	connected, err := i.device.GetConnected()
+	if err != nil {
+		return err
+	}
+	if !connected {
 		return ErrNotConnected
 	}
 	if char == nil {