From 366cbd11a40a6a3fde5d0dc803ca6895859ed188 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Wed, 27 Feb 2019 01:48:58 +0100 Subject: [PATCH] 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") } --- main.go | 5 +++++ tun/tun.go | 2 +- tun/tun_darwin.go | 41 ++++++++--------------------------- tun/tun_freebsd.go | 38 ++++++-------------------------- tun/tun_linux.go | 54 +++++++++++----------------------------------- tun/tun_openbsd.go | 37 +++++-------------------------- 6 files changed, 39 insertions(+), 138 deletions(-) diff --git a/main.go b/main.go index 23a1d2d..08f8cc6 100644 --- 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) }() diff --git a/tun/tun.go b/tun/tun.go index d9c3c15..3493b48 100644 --- a/tun/tun.go +++ b/tun/tun.go @@ -38,4 +38,4 @@ func (tun *nativeTun) operateOnFd(fn func(fd uintptr)) { if err != nil { tun.errors <- fmt.Errorf("unable to control sysconn for tunfile: %s", err.Error()) } -} \ No newline at end of file +} diff --git a/tun/tun_darwin.go b/tun/tun_darwin.go index 1190a9d..8cb2981 100644 --- 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) @@ -312,10 +292,7 @@ func (tun *nativeTun) Close() error { if err1 != nil { return err1 } - if err2 != nil { - return err2 - } - return err3 + return err2 } func (tun *nativeTun) setMTU(n int) error { diff --git a/tun/tun_freebsd.go b/tun/tun_freebsd.go index 1aec123..9e5c5ad 100644 --- 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) @@ -446,10 +423,7 @@ func (tun *nativeTun) Close() error { if err2 != nil { return err2 } - if err3 != nil { - return err3 - } - return err4 + return err3 } func (tun *nativeTun) setMTU(n int) error { diff --git a/tun/tun_linux.go b/tun/tun_linux.go index abdcce2..8dcad6b 100644 --- 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 + return err2 } 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( - unix.SYS_IOCTL, - nfd, - uintptr(unix.TUNSETIFF), - uintptr(unsafe.Pointer(&ifr[0])), - ) + var errno syscall.Errno + (&nativeTun{tunFile: tunFile}).operateOnFd(func(fd uintptr) { + _, _, errno = unix.Syscall( + unix.SYS_IOCTL, + 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() diff --git a/tun/tun_openbsd.go b/tun/tun_openbsd.go index b10c460..4e740c5 100644 --- 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) @@ -274,10 +250,7 @@ func (tun *nativeTun) Close() error { if err1 != nil { return err1 } - if err2 != nil { - return err2 - } - return err3 + return err2 } func (tun *nativeTun) setMTU(n int) error {