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")
}
This commit is contained in:
Jason A. Donenfeld 2019-02-27 01:48:58 +01:00
parent ab0f442daf
commit 366cbd11a4
6 changed files with 39 additions and 138 deletions

View file

@ -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)
}()

View file

@ -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 {

View file

@ -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

View file

@ -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()

View file

@ -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