tun: use netpoll instead of rwcancel

The new sysconn function of Go 1.12 makes this possible: package main import "log" import "os" import "unsafe" import "time" import "syscall" import "sync" import "golang.org/x/sys/unix" func main() { fd, err := os.OpenFile("/dev/net/tun", os.O_RDWR, 0) if err != nil { log.Fatal(err) } var ifr [unix.IFNAMSIZ + 64]byte copy(ifr[:], []byte("cheese")) *(*uint16)(unsafe.Pointer(&ifr[unix.IFNAMSIZ])) = unix.IFF_TUN var errno syscall.Errno s, _ := fd.SyscallConn() s.Control(func(fd uintptr) { _, _, errno = unix.Syscall( unix.SYS_IOCTL, fd, uintptr(unix.TUNSETIFF), uintptr(unsafe.Pointer(&ifr[0])), ) }) if errno != 0 { log.Fatal(errno) } b := [4]byte{} wait := sync.WaitGroup{} wait.Add(1) go func() { _, err := fd.Read(b[:]) log.Print("Read errored: ", err) wait.Done() }() time.Sleep(time.Second) log.Print("Closing") err = fd.Close() if err != nil { log.Print("Close errored: " , err) } wait.Wait() log.Print("Exiting") }
2025-10-27 02:10:26 +08:00 · 2019-02-27 01:48:58 +01:00
parent ab0f442daf
commit 366cbd11a4
6 changed files with 39 additions and 138 deletions
--- a/main.go
+++ b/main.go
@@ -145,6 +145,11 @@ func main() {
 			return nil, err
 		}

+		err = syscall.SetNonblock(int(fd), true)
+		if err != nil {
+			return nil, err
+		}
+
 		file := os.NewFile(uintptr(fd), "")
 		return tun.CreateTUNFromFile(file, DefaultMTU)
 	}()
--- a/tun/tun_darwin.go
+++ b/tun/tun_darwin.go
@@ -6,11 +6,9 @@
 package tun

 import (
-	"errors"
 	"fmt"
 	"golang.org/x/net/ipv6"
 	"golang.org/x/sys/unix"
-	"golang.zx2c4.com/wireguard/rwcancel"
 	"io/ioutil"
 	"net"
 	"os"
@@ -36,7 +34,6 @@ type sockaddrCtl struct {
 type nativeTun struct {
 	name        string
 	tunFile     *os.File
-	rwcancel    *rwcancel.RWCancel
 	events      chan TUNEvent
 	errors      chan error
 	routeSocket int
@@ -154,6 +151,10 @@ func CreateTUN(name string, mtu int) (TUNDevice, error) {
 		return nil, fmt.Errorf("SYS_CONNECT: %v", errno)
 	}

+	err = syscall.SetNonblock(fd, true)
+	if err != nil {
+		return nil, err
+	}
 	tun, err := CreateTUNFromFile(os.NewFile(uintptr(fd), ""), mtu)

 	if err == nil && name == "utun" {
@@ -191,14 +192,6 @@ func CreateTUNFromFile(file *os.File, mtu int) (TUNDevice, error) {
 		return nil, err
 	}

-	tun.operateOnFd(func (fd uintptr) {
-		tun.rwcancel, err = rwcancel.NewRWCancel(int(fd))
-	})
-	if err != nil {
-		tun.tunFile.Close()
-		return nil, err
-	}
-
 	tun.routeSocket, err = unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
 	if err != nil {
 		tun.tunFile.Close()
@@ -249,7 +242,7 @@ func (tun *nativeTun) Events() chan TUNEvent {
 	return tun.events
 }

-func (tun *nativeTun) doRead(buff []byte, offset int) (int, error) {
+func (tun *nativeTun) Read(buff []byte, offset int) (int, error) {
 	select {
 	case err := <-tun.errors:
 		return 0, err
@@ -263,18 +256,6 @@ func (tun *nativeTun) doRead(buff []byte, offset int) (int, error) {
 	}
 }

-func (tun *nativeTun) Read(buff []byte, offset int) (int, error) {
-	for {
-		n, err := tun.doRead(buff, offset)
-		if err == nil || !rwcancel.RetryAfterError(err) {
-			return n, err
-		}
-		if !tun.rwcancel.ReadyRead() {
-			return 0, errors.New("tun device closed")
-		}
-	}
-}
-
 func (tun *nativeTun) Write(buff []byte, offset int) (int, error) {

 	// reserve space for header
@@ -299,12 +280,11 @@ func (tun *nativeTun) Write(buff []byte, offset int) (int, error) {
 }

 func (tun *nativeTun) Close() error {
-	var err3 error
-	err1 := tun.rwcancel.Cancel()
-	err2 := tun.tunFile.Close()
+	var err2 error
+	err1 := tun.tunFile.Close()
 	if tun.routeSocket != -1 {
 		unix.Shutdown(tun.routeSocket, unix.SHUT_RDWR)
-		err3 = unix.Close(tun.routeSocket)
+		err2 = unix.Close(tun.routeSocket)
 		tun.routeSocket = -1
 	} else if tun.events != nil {
 		close(tun.events)
@@ -312,11 +292,8 @@ func (tun *nativeTun) Close() error {
 	if err1 != nil {
 		return err1
 	}
-	if err2 != nil {
 	return err2
 }
-	return err3
-}

 func (tun *nativeTun) setMTU(n int) error {

--- a/tun/tun_freebsd.go
+++ b/tun/tun_freebsd.go
@@ -11,7 +11,6 @@ import (
 	"fmt"
 	"golang.org/x/net/ipv6"
 	"golang.org/x/sys/unix"
-	"golang.zx2c4.com/wireguard/rwcancel"
 	"net"
 	"os"
 	"syscall"
@@ -52,7 +51,6 @@ type ifstat struct {
 type nativeTun struct {
 	name        string
 	tunFile     *os.File
-	rwcancel    *rwcancel.RWCancel
 	events      chan TUNEvent
 	errors      chan error
 	routeSocket int
@@ -333,14 +331,6 @@ func CreateTUNFromFile(file *os.File, mtu int) (TUNDevice, error) {
 		return nil, err
 	}

-	tun.operateOnFd(func(fd uintptr) {
-		tun.rwcancel, err = rwcancel.NewRWCancel(int(fd))
-	})
-	if err != nil {
-		tun.tunFile.Close()
-		return nil, err
-	}
-
 	tun.routeSocket, err = unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
 	if err != nil {
 		tun.tunFile.Close()
@@ -379,7 +369,7 @@ func (tun *nativeTun) Events() chan TUNEvent {
 	return tun.events
 }

-func (tun *nativeTun) doRead(buff []byte, offset int) (int, error) {
+func (tun *nativeTun) Read(buff []byte, offset int) (int, error) {
 	select {
 	case err := <-tun.errors:
 		return 0, err
@@ -393,18 +383,6 @@ func (tun *nativeTun) doRead(buff []byte, offset int) (int, error) {
 	}
 }

-func (tun *nativeTun) Read(buff []byte, offset int) (int, error) {
-	for {
-		n, err := tun.doRead(buff, offset)
-		if err == nil || !rwcancel.RetryAfterError(err) {
-			return n, err
-		}
-		if !tun.rwcancel.ReadyRead() {
-			return 0, errors.New("tun device closed")
-		}
-	}
-}
-
 func (tun *nativeTun) Write(buff []byte, offset int) (int, error) {

 	// reserve space for header
@@ -429,13 +407,12 @@ func (tun *nativeTun) Write(buff []byte, offset int) (int, error) {
 }

 func (tun *nativeTun) Close() error {
-	var err4 error
-	err1 := tun.rwcancel.Cancel()
-	err2 := tun.tunFile.Close()
-	err3 := tunDestroy(tun.name)
+	var err3 error
+	err1 := tun.tunFile.Close()
+	err2 := tunDestroy(tun.name)
 	if tun.routeSocket != -1 {
 		unix.Shutdown(tun.routeSocket, unix.SHUT_RDWR)
-		err4 = unix.Close(tun.routeSocket)
+		err3 = unix.Close(tun.routeSocket)
 		tun.routeSocket = -1
 	} else if tun.events != nil {
 		close(tun.events)
@@ -446,11 +423,8 @@ func (tun *nativeTun) Close() error {
 	if err2 != nil {
 		return err2
 	}
-	if err3 != nil {
 	return err3
 }
-	return err4
-}

 func (tun *nativeTun) setMTU(n int) error {
 	// open datagram socket
--- a/tun/tun_linux.go
+++ b/tun/tun_linux.go
@@ -31,7 +31,6 @@ const (

 type nativeTun struct {
 	tunFile                 *os.File
-	fdCancel                *rwcancel.RWCancel
 	index                   int32         // if index
 	name                    string        // name of interface
 	errors                  chan error    // async error handling
@@ -307,7 +306,7 @@ func (tun *nativeTun) Write(buff []byte, offset int) (int, error) {
 	return tun.tunFile.Write(buff)
 }

-func (tun *nativeTun) doRead(buff []byte, offset int) (int, error) {
+func (tun *nativeTun) Read(buff []byte, offset int) (int, error) {
 	select {
 	case err := <-tun.errors:
 		return 0, err
@@ -325,18 +324,6 @@ func (tun *nativeTun) doRead(buff []byte, offset int) (int, error) {
 	}
 }

-func (tun *nativeTun) Read(buff []byte, offset int) (int, error) {
-	for {
-		n, err := tun.doRead(buff, offset)
-		if err == nil || !rwcancel.RetryAfterError(err) {
-			return n, err
-		}
-		if !tun.fdCancel.ReadyRead() {
-			return 0, errors.New("tun device closed")
-		}
-	}
-}
-
 func (tun *nativeTun) Events() chan TUNEvent {
 	return tun.events
 }
@@ -352,30 +339,20 @@ func (tun *nativeTun) Close() error {
 		close(tun.events)
 	}
 	err2 := tun.tunFile.Close()
-	err3 := tun.fdCancel.Cancel()

 	if err1 != nil {
 		return err1
 	}
-	if err2 != nil {
 	return err2
 }
-	return err3
-}

 func CreateTUN(name string, mtu int) (TUNDevice, error) {
-	nfd, err := unix.Open(cloneDevicePath, os.O_RDWR, 0)
-	if err != nil {
-		return nil, err
-	}
-
-	fd := os.NewFile(uintptr(nfd), cloneDevicePath)
+	tunFile, err := os.OpenFile(cloneDevicePath, os.O_RDWR, 0)
 	if err != nil {
 		return nil, err
 	}

 	// create new device
-
 	var ifr [ifReqSize]byte
 	var flags uint16 = unix.IFF_TUN // | unix.IFF_NO_PI (disabled for TUN status hack)
 	nameBytes := []byte(name)
@@ -385,17 +362,20 @@ func CreateTUN(name string, mtu int) (TUNDevice, error) {
 	copy(ifr[:], nameBytes)
 	*(*uint16)(unsafe.Pointer(&ifr[unix.IFNAMSIZ])) = flags

-	_, _, errno := unix.Syscall(
+	var errno syscall.Errno
+	(&nativeTun{tunFile: tunFile}).operateOnFd(func(fd uintptr) {
+		_, _, errno = unix.Syscall(
 			unix.SYS_IOCTL,
-		nfd,
+			fd,
 			uintptr(unix.TUNSETIFF),
 			uintptr(unsafe.Pointer(&ifr[0])),
 		)
+	})
 	if errno != 0 {
 		return nil, errno
 	}

-	return CreateTUNFromFile(fd, mtu)
+	return CreateTUNFromFile(tunFile, mtu)
 }

 func CreateTUNFromFile(file *os.File, mtu int) (TUNDevice, error) {
@@ -408,14 +388,6 @@ func CreateTUNFromFile(file *os.File, mtu int) (TUNDevice, error) {
 	}
 	var err error

-	tun.operateOnFd(func(fd uintptr) {
-		tun.fdCancel, err = rwcancel.NewRWCancel(int(fd))
-	})
-	if err != nil {
-		tun.tunFile.Close()
-		return nil, err
-	}
-
 	_, err = tun.Name()
 	if err != nil {
 		tun.tunFile.Close()
--- a/tun/tun_openbsd.go
+++ b/tun/tun_openbsd.go
@@ -6,11 +6,9 @@
 package tun

 import (
-	"errors"
 	"fmt"
 	"golang.org/x/net/ipv6"
 	"golang.org/x/sys/unix"
-	"golang.zx2c4.com/wireguard/rwcancel"
 	"io/ioutil"
 	"net"
 	"os"
@@ -30,7 +28,6 @@ const _TUNSIFMODE = 0x8004745d
 type nativeTun struct {
 	name        string
 	tunFile     *os.File
-	rwcancel    *rwcancel.RWCancel
 	events      chan TUNEvent
 	errors      chan error
 	routeSocket int
@@ -167,14 +164,6 @@ func CreateTUNFromFile(file *os.File, mtu int) (TUNDevice, error) {
 		return nil, err
 	}

-	tun.operateOnFd(func(fd uintptr) {
-		tun.rwcancel, err = rwcancel.NewRWCancel(int(fd))
-	})
-	if err != nil {
-		tun.tunFile.Close()
-		return nil, err
-	}
-
 	tun.routeSocket, err = unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
 	if err != nil {
 		tun.tunFile.Close()
@@ -211,7 +200,7 @@ func (tun *nativeTun) Events() chan TUNEvent {
 	return tun.events
 }

-func (tun *nativeTun) doRead(buff []byte, offset int) (int, error) {
+func (tun *nativeTun) Read(buff []byte, offset int) (int, error) {
 	select {
 	case err := <-tun.errors:
 		return 0, err
@@ -225,18 +214,6 @@ func (tun *nativeTun) doRead(buff []byte, offset int) (int, error) {
 	}
 }

-func (tun *nativeTun) Read(buff []byte, offset int) (int, error) {
-	for {
-		n, err := tun.doRead(buff, offset)
-		if err == nil || !rwcancel.RetryAfterError(err) {
-			return n, err
-		}
-		if !tun.rwcancel.ReadyRead() {
-			return 0, errors.New("tun device closed")
-		}
-	}
-}
-
 func (tun *nativeTun) Write(buff []byte, offset int) (int, error) {

 	// reserve space for header
@@ -261,12 +238,11 @@ func (tun *nativeTun) Write(buff []byte, offset int) (int, error) {
 }

 func (tun *nativeTun) Close() error {
-	var err3 error
-	err1 := tun.rwcancel.Cancel()
-	err2 := tun.tunFile.Close()
+	var err2 error
+	err1 := tun.tunFile.Close()
 	if tun.routeSocket != -1 {
 		unix.Shutdown(tun.routeSocket, unix.SHUT_RDWR)
-		err3 = unix.Close(tun.routeSocket)
+		err2 = unix.Close(tun.routeSocket)
 		tun.routeSocket = -1
 	} else if tun.events != nil {
 		close(tun.events)
@@ -274,11 +250,8 @@ func (tun *nativeTun) Close() error {
 	if err1 != nil {
 		return err1
 	}
-	if err2 != nil {
 	return err2
 }
-	return err3
-}

 func (tun *nativeTun) setMTU(n int) error {
 	// open datagram socket