Merge pull request #42 from mysteriumnetwork/check-tun-status

Check if device exists before fetching state

openvpn/tunnel/setup_tun_linux.go

@@ -24,6 +24,8 @@ import (
 	"strconv"
 
 	log "github.com/cihub/seelog"
+	"github.com/pkg/errors"
+
 	"github.com/mysteriumnetwork/go-openvpn/openvpn/config"
 )
 
@@ -82,22 +84,26 @@ func (service *LinuxTunDeviceManager) Stop() {
 func (service *LinuxTunDeviceManager) createTunDevice(device tunDevice) (err error) {
 	err = service.createDeviceNode()
 	if err != nil {
-		return err
+		return errors.Wrap(err, "failed to create device node")
 	}
 
 	exists, err := service.deviceExists(device)
 	if err != nil {
-		return err
+		return errors.Wrap(err, "failed to check if device exists")
 	}
 
-	used, err := service.deviceUsed(device)
-	if err != nil {
-		return
+	var used bool
+
+	if exists {
+		used, err = service.deviceUsed(device)
+		if err != nil {
+			return errors.Wrap(err, "failed to check device used status")
+		}
 	}
 
 	if exists && !used {
 		log.Info(tunLogPrefix, device.Name+" device already exists, but not used, attempting to use it")
-		return
+		return nil
 	} else if used {
 		return log.Error("failed to get free tunnel device")
 	}
@@ -121,7 +127,7 @@ func (service *LinuxTunDeviceManager) deviceExists(device tunDevice) (exists boo
 	return false, err
 }
 
-func (service *LinuxTunDeviceManager) deviceUsed(device tunDevice) (exists bool, err error) {
+func (service *LinuxTunDeviceManager) deviceUsed(device tunDevice) (used bool, err error) {
 	contents, err := ioutil.ReadFile("/sys/class/net/" + device.Name + "/carrier")
 	if err != nil {
 		return false, err