377 lines
6.7 KiB
Go
377 lines
6.7 KiB
Go
/* SPDX-License-Identifier: MIT
|
|
*
|
|
* Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
|
|
*/
|
|
|
|
package tun
|
|
|
|
import (
|
|
"fmt"
|
|
"io/ioutil"
|
|
"net"
|
|
"os"
|
|
"syscall"
|
|
"unsafe"
|
|
|
|
"golang.org/x/net/ipv6"
|
|
"golang.org/x/sys/unix"
|
|
)
|
|
|
|
const utunControlName = "com.apple.net.utun_control"
|
|
|
|
// _CTLIOCGINFO value derived from /usr/include/sys/{kern_control,ioccom}.h
|
|
const _CTLIOCGINFO = (0x40000000 | 0x80000000) | ((100 & 0x1fff) << 16) | uint32(byte('N'))<<8 | 3
|
|
|
|
// sockaddr_ctl specifeid in /usr/include/sys/kern_control.h
|
|
type sockaddrCtl struct {
|
|
scLen uint8
|
|
scFamily uint8
|
|
ssSysaddr uint16
|
|
scID uint32
|
|
scUnit uint32
|
|
scReserved [5]uint32
|
|
}
|
|
|
|
type NativeTun struct {
|
|
name string
|
|
tunFile *os.File
|
|
events chan Event
|
|
errors chan error
|
|
routeSocket int
|
|
}
|
|
|
|
var sockaddrCtlSize uintptr = 32
|
|
|
|
func (tun *NativeTun) routineRouteListener(tunIfindex int) {
|
|
var (
|
|
statusUp bool
|
|
statusMTU int
|
|
)
|
|
|
|
defer func() {
|
|
close(tun.events)
|
|
tun.routeSocket = -1
|
|
}()
|
|
|
|
data := make([]byte, os.Getpagesize())
|
|
for {
|
|
retry:
|
|
n, err := unix.Read(tun.routeSocket, data)
|
|
if err != nil {
|
|
if errno, ok := err.(syscall.Errno); ok && errno == syscall.EINTR {
|
|
goto retry
|
|
}
|
|
tun.errors <- err
|
|
return
|
|
}
|
|
|
|
if n < 14 {
|
|
continue
|
|
}
|
|
|
|
if data[3 /* type */] != unix.RTM_IFINFO {
|
|
continue
|
|
}
|
|
ifindex := int(*(*uint16)(unsafe.Pointer(&data[12 /* ifindex */])))
|
|
if ifindex != tunIfindex {
|
|
continue
|
|
}
|
|
|
|
iface, err := net.InterfaceByIndex(ifindex)
|
|
if err != nil {
|
|
tun.errors <- err
|
|
return
|
|
}
|
|
|
|
// Up / Down event
|
|
up := (iface.Flags & net.FlagUp) != 0
|
|
if up != statusUp && up {
|
|
tun.events <- EventUp
|
|
}
|
|
if up != statusUp && !up {
|
|
tun.events <- EventDown
|
|
}
|
|
statusUp = up
|
|
|
|
// MTU changes
|
|
if iface.MTU != statusMTU {
|
|
tun.events <- EventMTUUpdate
|
|
}
|
|
statusMTU = iface.MTU
|
|
}
|
|
}
|
|
|
|
func CreateTUN(name string, mtu int) (Device, error) {
|
|
ifIndex := -1
|
|
if name != "utun" {
|
|
_, err := fmt.Sscanf(name, "utun%d", &ifIndex)
|
|
if err != nil || ifIndex < 0 {
|
|
return nil, fmt.Errorf("Interface name must be utun[0-9]*")
|
|
}
|
|
}
|
|
|
|
fd, err := unix.Socket(unix.AF_SYSTEM, unix.SOCK_DGRAM, 2)
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
var ctlInfo = &struct {
|
|
ctlID uint32
|
|
ctlName [96]byte
|
|
}{}
|
|
|
|
copy(ctlInfo.ctlName[:], []byte(utunControlName))
|
|
|
|
_, _, errno := unix.Syscall(
|
|
unix.SYS_IOCTL,
|
|
uintptr(fd),
|
|
uintptr(_CTLIOCGINFO),
|
|
uintptr(unsafe.Pointer(ctlInfo)),
|
|
)
|
|
|
|
if errno != 0 {
|
|
return nil, fmt.Errorf("_CTLIOCGINFO: %v", errno)
|
|
}
|
|
|
|
sc := sockaddrCtl{
|
|
scLen: uint8(sockaddrCtlSize),
|
|
scFamily: unix.AF_SYSTEM,
|
|
ssSysaddr: 2,
|
|
scID: ctlInfo.ctlID,
|
|
scUnit: uint32(ifIndex) + 1,
|
|
}
|
|
|
|
scPointer := unsafe.Pointer(&sc)
|
|
|
|
_, _, errno = unix.RawSyscall(
|
|
unix.SYS_CONNECT,
|
|
uintptr(fd),
|
|
uintptr(scPointer),
|
|
uintptr(sockaddrCtlSize),
|
|
)
|
|
|
|
if errno != 0 {
|
|
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" {
|
|
fname := os.Getenv("WG_TUN_NAME_FILE")
|
|
if fname != "" {
|
|
ioutil.WriteFile(fname, []byte(tun.(*NativeTun).name+"\n"), 0400)
|
|
}
|
|
}
|
|
|
|
return tun, err
|
|
}
|
|
|
|
func CreateTUNFromFile(file *os.File, mtu int) (Device, error) {
|
|
tun := &NativeTun{
|
|
tunFile: file,
|
|
events: make(chan Event, 10),
|
|
errors: make(chan error, 5),
|
|
}
|
|
|
|
name, err := tun.Name()
|
|
if err != nil {
|
|
tun.tunFile.Close()
|
|
return nil, err
|
|
}
|
|
|
|
tunIfindex, err := func() (int, error) {
|
|
iface, err := net.InterfaceByName(name)
|
|
if err != nil {
|
|
return -1, err
|
|
}
|
|
return iface.Index, nil
|
|
}()
|
|
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()
|
|
return nil, err
|
|
}
|
|
|
|
go tun.routineRouteListener(tunIfindex)
|
|
|
|
if mtu > 0 {
|
|
err = tun.setMTU(mtu)
|
|
if err != nil {
|
|
tun.Close()
|
|
return nil, err
|
|
}
|
|
}
|
|
|
|
return tun, nil
|
|
}
|
|
|
|
func (tun *NativeTun) Name() (string, error) {
|
|
var ifName struct {
|
|
name [16]byte
|
|
}
|
|
ifNameSize := uintptr(16)
|
|
|
|
var errno syscall.Errno
|
|
tun.operateOnFd(func(fd uintptr) {
|
|
_, _, errno = unix.Syscall6(
|
|
unix.SYS_GETSOCKOPT,
|
|
fd,
|
|
2, /* #define SYSPROTO_CONTROL 2 */
|
|
2, /* #define UTUN_OPT_IFNAME 2 */
|
|
uintptr(unsafe.Pointer(&ifName)),
|
|
uintptr(unsafe.Pointer(&ifNameSize)), 0)
|
|
})
|
|
|
|
if errno != 0 {
|
|
return "", fmt.Errorf("SYS_GETSOCKOPT: %v", errno)
|
|
}
|
|
|
|
tun.name = string(ifName.name[:ifNameSize-1])
|
|
return tun.name, nil
|
|
}
|
|
|
|
func (tun *NativeTun) File() *os.File {
|
|
return tun.tunFile
|
|
}
|
|
|
|
func (tun *NativeTun) Events() chan Event {
|
|
return tun.events
|
|
}
|
|
|
|
func (tun *NativeTun) Read(buff []byte, offset int) (int, error) {
|
|
select {
|
|
case err := <-tun.errors:
|
|
return 0, err
|
|
default:
|
|
buff := buff[offset-4:]
|
|
n, err := tun.tunFile.Read(buff[:])
|
|
if n < 4 {
|
|
return 0, err
|
|
}
|
|
return n - 4, err
|
|
}
|
|
}
|
|
|
|
func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
|
|
|
|
// reserve space for header
|
|
|
|
buff = buff[offset-4:]
|
|
|
|
// add packet information header
|
|
|
|
buff[0] = 0x00
|
|
buff[1] = 0x00
|
|
buff[2] = 0x00
|
|
|
|
if buff[4]>>4 == ipv6.Version {
|
|
buff[3] = unix.AF_INET6
|
|
} else {
|
|
buff[3] = unix.AF_INET
|
|
}
|
|
|
|
// write
|
|
|
|
return tun.tunFile.Write(buff)
|
|
}
|
|
|
|
func (tun *NativeTun) Flush() error {
|
|
// TODO: can flushing be implemented by buffering and using sendmmsg?
|
|
return nil
|
|
}
|
|
|
|
func (tun *NativeTun) Close() error {
|
|
var err2 error
|
|
err1 := tun.tunFile.Close()
|
|
if tun.routeSocket != -1 {
|
|
unix.Shutdown(tun.routeSocket, unix.SHUT_RDWR)
|
|
err2 = unix.Close(tun.routeSocket)
|
|
} else if tun.events != nil {
|
|
close(tun.events)
|
|
}
|
|
if err1 != nil {
|
|
return err1
|
|
}
|
|
return err2
|
|
}
|
|
|
|
func (tun *NativeTun) setMTU(n int) error {
|
|
|
|
// open datagram socket
|
|
|
|
var fd int
|
|
|
|
fd, err := unix.Socket(
|
|
unix.AF_INET,
|
|
unix.SOCK_DGRAM,
|
|
0,
|
|
)
|
|
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
defer unix.Close(fd)
|
|
|
|
// do ioctl call
|
|
|
|
var ifr [32]byte
|
|
copy(ifr[:], tun.name)
|
|
*(*uint32)(unsafe.Pointer(&ifr[unix.IFNAMSIZ])) = uint32(n)
|
|
_, _, errno := unix.Syscall(
|
|
unix.SYS_IOCTL,
|
|
uintptr(fd),
|
|
uintptr(unix.SIOCSIFMTU),
|
|
uintptr(unsafe.Pointer(&ifr[0])),
|
|
)
|
|
|
|
if errno != 0 {
|
|
return fmt.Errorf("failed to set MTU on %s", tun.name)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (tun *NativeTun) MTU() (int, error) {
|
|
|
|
// open datagram socket
|
|
|
|
fd, err := unix.Socket(
|
|
unix.AF_INET,
|
|
unix.SOCK_DGRAM,
|
|
0,
|
|
)
|
|
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
defer unix.Close(fd)
|
|
|
|
// do ioctl call
|
|
|
|
var ifr [64]byte
|
|
copy(ifr[:], tun.name)
|
|
_, _, errno := unix.Syscall(
|
|
unix.SYS_IOCTL,
|
|
uintptr(fd),
|
|
uintptr(unix.SIOCGIFMTU),
|
|
uintptr(unsafe.Pointer(&ifr[0])),
|
|
)
|
|
if errno != 0 {
|
|
return 0, fmt.Errorf("failed to get MTU on %s", tun.name)
|
|
}
|
|
|
|
return int(*(*int32)(unsafe.Pointer(&ifr[16]))), nil
|
|
}
|