tun: simplify and combine creation logic on Linux

diff --git a/tun_linux.go b/tun_linux.go
index e3e151299bd13c84182ace6a6eadcc54bb3a56ea..18994ccf69c31b32c7a9c1d8acd31095f5844512 100644 (file)
--- a/tun_linux.go
+++ b/tun_linux.go
@@ -20,7 +20,6 @@ import (
        "net"
        "os"
        "strconv"
-       "strings"
        "syscall"
        "time"
        "unsafe"
@@ -361,6 +360,7 @@ func (tun *NativeTun) doRead(buff []byte, offset int) (int, error) {
        }
 }
 
+/* https://golang.org/src/crypto/rand/eagain.go */
 func unixIsEAGAIN(err error) bool {
        if pe, ok := err.(*os.PathError); ok {
                if errno, ok := pe.Err.(syscall.Errno); ok && errno == syscall.EAGAIN {
@@ -395,57 +395,18 @@ func (tun *NativeTun) Close() error {
        return nil
 }
 
-func CreateTUNFromFile(fd *os.File) (TUNDevice, error) {
-       device := &NativeTun{
-               fd:     fd,
-               events: make(chan TUNEvent, 5),
-               errors: make(chan error, 5),
-               nopi:   false,
-       }
-       var err error
-
-       err = syscall.SetNonblock(int(fd.Fd()), true)
-       if err != nil {
-               return nil, err
-       }
-
-       _, err = device.Name()
-       if err != nil {
-               return nil, err
-       }
-
-       device.closingReader, device.closingWriter, err = os.Pipe()
-       if err != nil {
-               return nil, err
-       }
-
-       // start event listener
-
-       device.index, err = getIFIndex(device.name)
-       if err != nil {
-               return nil, err
-       }
-
-       go device.RoutineNetlinkListener()
-       go device.RoutineHackListener() // cross namespace
-
-       // set default MTU
-
-       return device, device.setMTU(DefaultMTU)
-}
-
 func CreateTUN(name string) (TUNDevice, error) {
 
        // open clone device
 
        // HACK: we open it as a raw Fd first, so that f.nonblock=false
        // when we make it into a file object.
-       nfd, err := syscall.Open(cloneDevicePath, os.O_RDWR, 0)
+       nfd, err := unix.Open(cloneDevicePath, os.O_RDWR, 0)
        if err != nil {
                return nil, err
        }
 
-       err = syscall.SetNonblock(nfd, true)
+       err = unix.SetNonblock(nfd, true)
        if err != nil {
                return nil, err
        }
@@ -476,17 +437,27 @@ func CreateTUN(name string) (TUNDevice, error) {
                return nil, errno
        }
 
-       // read (new) name of interface
+       return CreateTUNFromFile(fd)
+}
 
-       newName := string(ifr[:])
-       newName = newName[:strings.Index(newName, "\000")]
+func CreateTUNFromFile(fd *os.File) (TUNDevice, error) {
        device := &NativeTun{
                fd:     fd,
-               name:   newName,
                events: make(chan TUNEvent, 5),
                errors: make(chan error, 5),
                nopi:   false,
        }
+       var err error
+
+       err = unix.SetNonblock(int(fd.Fd()), true)
+       if err != nil {
+               return nil, err
+       }
+
+       _, err = device.Name()
+       if err != nil {
+               return nil, err
+       }
 
        device.closingReader, device.closingWriter, err = os.Pipe()
        if err != nil {