From 03f2e2614ad38317db77b499155995ee5e3d68c2 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Mon, 18 Mar 2019 02:42:00 -0600 Subject: tun: windows: wintun does iocp --- tun/tun_windows.go | 184 ++++++++++++++--------------------------------------- 1 file changed, 49 insertions(+), 135 deletions(-) (limited to 'tun/tun_windows.go') diff --git a/tun/tun_windows.go b/tun/tun_windows.go index 579e65c..81ba18e 100644 --- a/tun/tun_windows.go +++ b/tun/tun_windows.go @@ -35,18 +35,15 @@ type exchgBufWrite struct { } type NativeTun struct { - wt *wintun.Wintun - tunName string - signalName *uint16 - tunFile *os.File - tunLock sync.Mutex - rdBuff *exchgBufRead - wrBuff *exchgBufWrite - tunDataAvail windows.Handle - userClose windows.Handle - events chan TUNEvent - errors chan error - forcedMtu int + wt *wintun.Wintun + tunName string + tunFile *os.File + tunLock sync.Mutex + rdBuff *exchgBufRead + wrBuff *exchgBufWrite + events chan TUNEvent + errors chan error + forcedMtu int } func packetAlign(size uint32) uint32 { @@ -86,106 +83,51 @@ func CreateTUN(ifname string) (TUNDevice, error) { return nil, errors.New("Flushing interface failed: " + err.Error()) } - signalNameUTF16, err := windows.UTF16PtrFromString(wt.SignalEventName()) - if err != nil { - wt.DeleteInterface(0) - return nil, err - } - - // Create instance. - tun := &NativeTun{ - wt: wt, - tunName: wt.DataFileName(), - signalName: signalNameUTF16, - rdBuff: &exchgBufRead{}, - wrBuff: &exchgBufWrite{}, - events: make(chan TUNEvent, 10), - errors: make(chan error, 1), - forcedMtu: 1500, - } - - // Create close event. - tun.userClose, err = windows.CreateEvent(nil, 1 /*TRUE*/, 0 /*FALSE*/, nil) - if err != nil { - wt.DeleteInterface(0) - return nil, err - } - - return tun, nil + return &NativeTun{ + wt: wt, + tunName: wt.DataFileName(), + rdBuff: &exchgBufRead{}, + wrBuff: &exchgBufWrite{}, + events: make(chan TUNEvent, 10), + errors: make(chan error, 1), + forcedMtu: 1500, + }, nil } -func (tun *NativeTun) openTUN() error { +func (tun *NativeTun) openTUN() { for { - // Open interface data pipe. - // Data pipe must be opened first, as the interface data available event is created when somebody actually connects to the data pipe. - file, err := os.OpenFile(tun.tunName, os.O_RDWR|os.O_SYNC, 0600) + file, err := os.OpenFile(tun.tunName, os.O_RDWR, 0) if err != nil { - // After examining possible error conditions, many arose that were only temporary: windows.ERROR_FILE_NOT_FOUND, "read closed", etc. - // To simplify, we will enter a retry-loop on _any_ error until session is closed by user. - switch evt, e := windows.WaitForSingleObject(tun.userClose, 1000); evt { - case windows.WAIT_OBJECT_0, windows.WAIT_ABANDONED: - return errors.New("TUN closed") - case windows.WAIT_TIMEOUT: - continue - default: - return errors.New("Unexpected result from WaitForSingleObject: " + e.Error()) - } - } - - // Open interface data available event. - event, err := windows.OpenEvent(windows.SYNCHRONIZE, false, tun.signalName) - if err != nil { - file.Close() - return errors.New("Opening interface data ready event failed: " + err.Error()) + continue } - tun.tunFile = file - tun.tunDataAvail = event - - return nil } } func (tun *NativeTun) closeTUN() (err error) { - tun.tunLock.Lock() - defer tun.tunLock.Unlock() - - if tun.tunDataAvail != 0 { - // Close interface data ready event. - e := windows.CloseHandle(tun.tunDataAvail) - if err != nil { - err = e - } - - tun.tunDataAvail = 0 - } - if tun.tunFile != nil { - // Close interface data pipe. - e := tun.tunFile.Close() - if err != nil { - err = e + tun.tunLock.Lock() + defer tun.tunLock.Unlock() + if tun.tunFile == nil { + return } - + t := tun.tunFile tun.tunFile = nil + err = t.Close() } - return } -func (tun *NativeTun) getTUN() (*os.File, windows.Handle, error) { - tun.tunLock.Lock() - defer tun.tunLock.Unlock() - - if tun.tunFile == nil || tun.tunDataAvail == 0 { - // TUN device is not open (yet). - err := tun.openTUN() - if err != nil { - return nil, 0, err +func (tun *NativeTun) getTUN() (*os.File, error) { + if tun.tunFile == nil { + tun.tunLock.Lock() + defer tun.tunLock.Unlock() + if tun.tunFile != nil { + return tun.tunFile, nil } + tun.openTUN() } - - return tun.tunFile, tun.tunDataAvail, nil + return tun.tunFile, nil } func (tun *NativeTun) Name() (string, error) { @@ -201,24 +143,18 @@ func (tun *NativeTun) Events() chan TUNEvent { } func (tun *NativeTun) Close() error { - windows.SetEvent(tun.userClose) - err := windows.CloseHandle(tun.userClose) - - e := tun.closeTUN() - if err == nil { - err = e - } + err1 := tun.closeTUN() if tun.events != nil { close(tun.events) } - _, _, e = tun.wt.DeleteInterface(0) - if err == nil { - err = e + _, _, err2 := tun.wt.DeleteInterface(0) + if err1 == nil { + err1 = err2 } - return err + return err1 } func (tun *NativeTun) MTU() (int, error) { @@ -248,42 +184,16 @@ func (tun *NativeTun) Read(buff []byte, offset int) (int, error) { tun.rdBuff.avail = 0 continue } - packet = packet[:pSize] + packet = packet[packetExchangeAlignment : packetExchangeAlignment+size] // Copy data. - copy(buff[offset:], packet[packetExchangeAlignment:packetExchangeAlignment+size]) + copy(buff[offset:], packet) tun.rdBuff.offset += pSize return int(size), nil } - // Get TUN data ready event. - _, tunDataAvail, err := tun.getTUN() - if err != nil { - return 0, err - } - - // Wait for user close or interface data. - r, err := windows.WaitForMultipleObjects([]windows.Handle{tun.userClose, tunDataAvail}, false, windows.INFINITE) - if err != nil { - return 0, errors.New("Waiting for data failed: " + err.Error()) - } - switch r { - case windows.WAIT_OBJECT_0 + 0, windows.WAIT_ABANDONED + 0: - return 0, errors.New("TUN closed") - case windows.WAIT_OBJECT_0 + 1: - // Data is available. - case windows.WAIT_ABANDONED + 1: - // TUN stopped. - tun.closeTUN() - case windows.WAIT_TIMEOUT: - // Congratulations, we reached infinity. Let's do it again! :) - continue - default: - return 0, errors.New("unexpected result from WaitForMultipleObjects") - } - // Get TUN data pipe. - file, _, err := tun.getTUN() + file, err := tun.getTUN() if err != nil { return 0, err } @@ -291,6 +201,9 @@ func (tun *NativeTun) Read(buff []byte, offset int) (int, error) { // Fill queue. n, err := file.Read(tun.rdBuff.data[:]) if err != nil { + if pe, ok := err.(*os.PathError); ok && pe.Err == os.ErrClosed { + return 0, err + } // TUN interface stopped, failed, etc. Retry. tun.rdBuff.avail = 0 tun.closeTUN() @@ -305,7 +218,7 @@ func (tun *NativeTun) Read(buff []byte, offset int) (int, error) { func (tun *NativeTun) flush() error { // Get TUN data pipe. - file, _, err := tun.getTUN() + file, err := tun.getTUN() if err != nil { return err } @@ -344,7 +257,8 @@ func (tun *NativeTun) putTunPacket(buff []byte) error { // Write packet to the exchange buffer. packet := tun.wrBuff.data[tun.wrBuff.offset : tun.wrBuff.offset+pSize] *(*uint32)(unsafe.Pointer(&packet[0])) = size - copy(packet[packetExchangeAlignment:packetExchangeAlignment+size], buff) + packet = packet[packetExchangeAlignment : packetExchangeAlignment+size] + copy(packet, buff) tun.wrBuff.packetNum++ tun.wrBuff.offset += pSize -- cgit v1.2.3-59-g8ed1b