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https://git.zx2c4.com/wireguard-go
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Align with go library layout
This commit is contained in:
Mathias Hall-Andersen
323
tun_darwin.go
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323
tun_darwin.go
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@@ -0,0 +1,323 @@
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/* Copyright (c) 2016, Song Gao <song@gao.io>
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* All rights reserved.
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*
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* Code from https://github.com/songgao/water
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*/
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package main
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import (
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"encoding/binary"
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"errors"
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"fmt"
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"golang.org/x/net/ipv4"
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"golang.org/x/net/ipv6"
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"golang.org/x/sys/unix"
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"io"
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"net"
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"os"
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"sync"
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"time"
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"unsafe"
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)
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const utunControlName = "com.apple.net.utun_control"
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// _CTLIOCGINFO value derived from /usr/include/sys/{kern_control,ioccom}.h
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const _CTLIOCGINFO = (0x40000000 | 0x80000000) | ((100 & 0x1fff) << 16) | uint32(byte('N'))<<8 | 3
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// sockaddr_ctl specifeid in /usr/include/sys/kern_control.h
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type sockaddrCtl struct {
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scLen uint8
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scFamily uint8
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ssSysaddr uint16
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scID uint32
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scUnit uint32
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scReserved [5]uint32
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}
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// NativeTUN is a hack to work around the first 4 bytes "packet
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// information" because there doesn't seem to be an IFF_NO_PI for darwin.
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type NativeTUN struct {
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name string
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f io.ReadWriteCloser
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mtu int
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rMu sync.Mutex
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rBuf []byte
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wMu sync.Mutex
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wBuf []byte
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events chan TUNEvent
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errors chan error
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}
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var sockaddrCtlSize uintptr = 32
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func CreateTUN(name string) (ifce TUNDevice, err error) {
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ifIndex := -1
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fmt.Sscanf(name, "utun%d", &ifIndex)
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if ifIndex < 0 {
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return nil, fmt.Errorf("error parsing interface name %s, must be utun[0-9]+", name)
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}
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fd, err := unix.Socket(unix.AF_SYSTEM, unix.SOCK_DGRAM, 2)
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if err != nil {
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return nil, fmt.Errorf("error in unix.Socket: %v", err)
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}
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var ctlInfo = &struct {
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ctlID uint32
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ctlName [96]byte
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}{}
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copy(ctlInfo.ctlName[:], []byte(utunControlName))
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_, _, errno := unix.Syscall(
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unix.SYS_IOCTL,
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uintptr(fd),
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uintptr(_CTLIOCGINFO),
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uintptr(unsafe.Pointer(ctlInfo)),
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)
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if errno != 0 {
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err = errno
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return nil, fmt.Errorf("error in unix.Syscall(unix.SYS_IOTL, ...): %v", err)
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}
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sc := sockaddrCtl{
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scLen: uint8(sockaddrCtlSize),
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scFamily: unix.AF_SYSTEM,
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ssSysaddr: 2,
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scID: ctlInfo.ctlID,
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scUnit: uint32(ifIndex) + 1,
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}
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scPointer := unsafe.Pointer(&sc)
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_, _, errno = unix.RawSyscall(
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unix.SYS_CONNECT,
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uintptr(fd),
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uintptr(scPointer),
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uintptr(sockaddrCtlSize),
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)
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if errno != 0 {
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err = errno
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return nil, fmt.Errorf("error in unix.RawSyscall(unix.SYS_CONNECT, ...): %v", err)
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}
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// read (new) name of interface
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var ifName struct {
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name [16]byte
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}
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ifNameSize := uintptr(16)
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_, _, errno = unix.Syscall6(
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unix.SYS_GETSOCKOPT,
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uintptr(fd),
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2, /* #define SYSPROTO_CONTROL 2 */
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2, /* #define UTUN_OPT_IFNAME 2 */
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uintptr(unsafe.Pointer(&ifName)),
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uintptr(unsafe.Pointer(&ifNameSize)), 0)
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if errno != 0 {
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err = errno
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return nil, fmt.Errorf("error in unix.Syscall6(unix.SYS_GETSOCKOPT, ...): %v", err)
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}
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device := &NativeTUN{
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name: string(ifName.name[:ifNameSize-1 /* -1 is for \0 */]),
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f: os.NewFile(uintptr(fd), string(ifName.name[:])),
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mtu: 1500,
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events: make(chan TUNEvent, 10),
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errors: make(chan error, 1),
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}
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// start listener
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go func(native *NativeTUN) {
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// TODO: Fix this very niave implementation
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var (
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statusUp bool
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statusMTU int
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)
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for ; ; time.Sleep(time.Second) {
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intr, err := net.InterfaceByName(device.name)
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if err != nil {
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native.errors <- err
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return
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}
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// Up / Down event
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up := (intr.Flags & net.FlagUp) != 0
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if up != statusUp && up {
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native.events <- TUNEventUp
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}
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if up != statusUp && !up {
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native.events <- TUNEventDown
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}
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statusUp = up
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// MTU changes
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if intr.MTU != statusMTU {
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native.events <- TUNEventMTUUpdate
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}
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statusMTU = intr.MTU
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}
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}(device)
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// set default MTU
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err = device.setMTU(DefaultMTU)
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return device, err
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}
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var _ io.ReadWriteCloser = (*NativeTUN)(nil)
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func (t *NativeTUN) Events() chan TUNEvent {
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return t.events
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}
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func (t *NativeTUN) Read(to []byte) (int, error) {
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t.rMu.Lock()
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defer t.rMu.Unlock()
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if cap(t.rBuf) < len(to)+4 {
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t.rBuf = make([]byte, len(to)+4)
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}
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t.rBuf = t.rBuf[:len(to)+4]
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n, err := t.f.Read(t.rBuf)
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copy(to, t.rBuf[4:])
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return n - 4, err
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}
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func (t *NativeTUN) Write(from []byte) (int, error) {
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if len(from) == 0 {
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return 0, unix.EIO
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}
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t.wMu.Lock()
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defer t.wMu.Unlock()
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if cap(t.wBuf) < len(from)+4 {
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t.wBuf = make([]byte, len(from)+4)
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}
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t.wBuf = t.wBuf[:len(from)+4]
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// determine the IP Family for the NULL L2 Header
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ipVer := from[0] >> 4
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if ipVer == ipv4.Version {
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t.wBuf[3] = unix.AF_INET
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} else if ipVer == ipv6.Version {
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t.wBuf[3] = unix.AF_INET6
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} else {
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return 0, errors.New("Unable to determine IP version from packet.")
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}
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copy(t.wBuf[4:], from)
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n, err := t.f.Write(t.wBuf)
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return n - 4, err
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}
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func (t *NativeTUN) Close() error {
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// lock to make sure no read/write is in process.
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t.rMu.Lock()
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defer t.rMu.Unlock()
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t.wMu.Lock()
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defer t.wMu.Unlock()
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return t.f.Close()
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}
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func (t *NativeTUN) Name() string {
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return t.name
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}
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func (t *NativeTUN) setMTU(n int) error {
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// open datagram socket
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var fd int
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fd, err := unix.Socket(
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unix.AF_INET,
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unix.SOCK_DGRAM,
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0,
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)
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if err != nil {
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return err
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}
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defer unix.Close(fd)
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// do ioctl call
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var ifr [32]byte
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copy(ifr[:], t.name)
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binary.LittleEndian.PutUint32(ifr[16:20], uint32(n))
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_, _, errno := unix.Syscall(
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unix.SYS_IOCTL,
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uintptr(fd),
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uintptr(unix.SIOCSIFMTU),
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uintptr(unsafe.Pointer(&ifr[0])),
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)
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if errno != 0 {
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return fmt.Errorf("Failed to set MTU on %s", t.name)
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}
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return nil
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}
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func (t *NativeTUN) MTU() (int, error) {
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// open datagram socket
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fd, err := unix.Socket(
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unix.AF_INET,
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unix.SOCK_DGRAM,
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0,
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)
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if err != nil {
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return 0, err
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}
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defer unix.Close(fd)
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// do ioctl call
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var ifr [64]byte
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copy(ifr[:], t.name)
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_, _, errno := unix.Syscall(
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unix.SYS_IOCTL,
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uintptr(fd),
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uintptr(unix.SIOCGIFMTU),
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uintptr(unsafe.Pointer(&ifr[0])),
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)
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if errno != 0 {
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return 0, fmt.Errorf("Failed to get MTU on %s", t.name)
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}
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// convert result to signed 32-bit int
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val := binary.LittleEndian.Uint32(ifr[16:20])
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if val >= (1 << 31) {
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return int(val-(1<<31)) - (1 << 31), nil
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}
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return int(val), nil
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}
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