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Add OpenBSD tun driver support

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This commit is contained in:
Jason A. Donenfeld 2018-05-22 15:17:35 +02:00
parent 794e494802
commit d6b694e161
6 changed files with 411 additions and 36 deletions
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6
README.md
View file

@ -32,7 +32,7 @@ This will run on Linux; however **YOU SHOULD NOT RUN THIS ON LINUX**. Instead us
### macOS
This runs on macOS using the utun driver. It does not yet support sticky sockets, and won't support fwmarks because of Darwin limitations. Since the utun driver cannot have arbitrary interface names, you must either use `utun[0-9]+` for an explicit interface name or `utun` to have the kernel select one for you. If you choose `utun` as the interface name, and the environment variable `WG_DARWIN_UTUN_NAME_FILE` is defined, then the actual name of the interface chosen by the kernel is written to the file specified by that variable.
This runs on macOS using the utun driver. It does not yet support sticky sockets, and won't support fwmarks because of Darwin limitations. Since the utun driver cannot have arbitrary interface names, you must either use `utun[0-9]+` for an explicit interface name or `utun` to have the kernel select one for you. If you choose `utun` as the interface name, and the environment variable `WG_TUN_NAME_FILE` is defined, then the actual name of the interface chosen by the kernel is written to the file specified by that variable.
### Windows
@ -42,6 +42,10 @@ It is currently a work in progress to strip out the beginnings of an experiment
This will run on FreeBSD. It does not yet support sticky sockets. Fwmark is mapped to `SO\_USER\_COOKIE`.
### OpenBSD
This will run on OpenBSD. It does not yet support sticky sockets. Fwmark is mapped to `SO\_RTABLE`. Since the tun driver cannot have arbitrary interface names, you must either use `tun[0-9]+` for an explicit interface name or `tun` to have the program select one for you. If you choose `tun` as the interface name, and the environment variable `WG_TUN_NAME_FILE` is defined, then the actual name of the interface chosen by the kernel is written to the file specified by that variable.
## Building
You can satisfy dependencies with either `go get -d -v` or `dep ensure -vendor-only`. Then run `make`. As this is a Go project, a `GOPATH` is required. For example, wireguard-go can be built with:

64
conn_default.go
View file

@ -140,35 +140,45 @@ func (bind *NativeBind) Send(buff []byte, endpoint Endpoint) error {
return err
}
func (bind *NativeBind) SetMark(mark uint32) error {
var fwmarkIoctl int
func init() {
if runtime.GOOS == "freebsd" {
fd4, err1 := bind.ipv4.SyscallConn()
fd6, err2 := bind.ipv6.SyscallConn()
if err1 != nil {
return err1
}
if err2 != nil {
return err2
}
err3 := fd4.Control(func(fd uintptr) {
err1 = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, 0x1015 /* unix.SO_USER_COOKIE */, int(mark))
})
err4 := fd6.Control(func(fd uintptr) {
err2 = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, 0x1015 /* unix.SO_USER_COOKIE */, int(mark))
})
if err1 != nil {
return err1
}
if err2 != nil {
return err2
}
if err3 != nil {
return err3
}
if err4 != nil {
return err4
}
fwmarkIoctl = 0x1015 /* unix.SO_USER_COOKIE */
} else if runtime.GOOS == "openbsd" {
fwmarkIoctl = 0x1021 /* unix.SO_RTABLE */
}
}
func (bind *NativeBind) SetMark(mark uint32) error {
if fwmarkIoctl == 0 {
return nil
}
fd4, err1 := bind.ipv4.SyscallConn()
fd6, err2 := bind.ipv6.SyscallConn()
if err1 != nil {
return err1
}
if err2 != nil {
return err2
}
err3 := fd4.Control(func(fd uintptr) {
err1 = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, fwmarkIoctl, int(mark))
})
err4 := fd6.Control(func(fd uintptr) {
err2 = unix.SetsockoptInt(int(fd), unix.SOL_SOCKET, fwmarkIoctl, int(mark))
})
if err1 != nil {
return err1
}
if err2 != nil {
return err2
}
if err3 != nil {
return err3
}
if err4 != nil {
return err4
}
return nil
}

2
tun_darwin.go
View file

@ -154,7 +154,7 @@ func CreateTUN(name string) (TUNDevice, error) {
tun, err := CreateTUNFromFile(os.NewFile(uintptr(fd), ""))
if err == nil && name == "utun" {
fname := os.Getenv("WG_DARWIN_UTUN_NAME_FILE")
fname := os.Getenv("WG_TUN_NAME_FILE")
if fname != "" {
ioutil.WriteFile(fname, []byte(tun.(*NativeTun).name+"\n"), 0400)
}

7
tun_freebsd.go
View file

@ -306,12 +306,7 @@ func CreateTUN(name string) (TUNDevice, error) {
return nil, fmt.Errorf("failed to rename %s to %s: %s", assignedName, name, errno.Error())
}
tun, err := CreateTUNFromFile(tunfile)
if err != nil {
return nil, err
}
return tun, err
return CreateTUNFromFile(tunfile)
}
func CreateTUNFromFile(file *os.File) (TUNDevice, error) {

366
tun_openbsd.go Normal file
View file

@ -0,0 +1,366 @@
/* SPDX-License-Identifier: GPL-2.0
*
* Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
package main
import (
"./rwcancel"
"errors"
"fmt"
"golang.org/x/net/ipv6"
"golang.org/x/sys/unix"
"io/ioutil"
"net"
"os"
"syscall"
"unsafe"
)
// Structure for iface mtu get/set ioctls
type ifreq_mtu struct {
Name [unix.IFNAMSIZ]byte
MTU uint32
Pad0 [12]byte
}
const _TUNSIFMODE = 0x8004745d
type NativeTun struct {
name string
fd *os.File
rwcancel *rwcancel.RWCancel
events chan TUNEvent
errors chan error
routeSocket int
}
func (tun *NativeTun) RoutineRouteListener(tunIfindex int) {
var (
statusUp bool
statusMTU int
)
defer close(tun.events)
data := make([]byte, os.Getpagesize())
for {
n, err := unix.Read(tun.routeSocket, data)
if err != nil {
tun.errors <- err
return
}
if n < 8 {
continue
}
if data[3 /* type */] != unix.RTM_IFINFO {
continue
}
ifindex := int(*(*uint16)(unsafe.Pointer(&data[6 /* 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 <- TUNEventUp
}
if up != statusUp && !up {
tun.events <- TUNEventDown
}
statusUp = up
// MTU changes
if iface.MTU != statusMTU {
tun.events <- TUNEventMTUUpdate
}
statusMTU = iface.MTU
}
}
func errorIsEBUSY(err error) bool {
if pe, ok := err.(*os.PathError); ok {
if errno, ok := pe.Err.(syscall.Errno); ok && errno == syscall.EBUSY {
return true
}
}
if errno, ok := err.(syscall.Errno); ok && errno == syscall.EBUSY {
return true
}
return false
}
func CreateTUN(name string) (TUNDevice, error) {
ifIndex := -1
if name != "tun" {
_, err := fmt.Sscanf(name, "tun%d", &ifIndex)
if err != nil || ifIndex < 0 {
return nil, fmt.Errorf("Interface name must be tun[0-9]*")
}
}
var tunfile *os.File
var err error
if ifIndex != -1 {
tunfile, err = os.OpenFile(fmt.Sprintf("/dev/tun%d", ifIndex), unix.O_RDWR, 0)
} else {
for ifIndex = 0; ifIndex < 256; ifIndex += 1 {
tunfile, err = os.OpenFile(fmt.Sprintf("/dev/tun%d", ifIndex), unix.O_RDWR, 0)
if err == nil || !errorIsEBUSY(err) {
break
}
}
}
if err != nil {
return nil, err
}
// Set TUN iface to broadcast mode
ifmodemode := unix.IFF_BROADCAST
_, _, errno := unix.Syscall(
unix.SYS_IOCTL,
uintptr(tunfile.Fd()),
uintptr(_TUNSIFMODE),
uintptr(unsafe.Pointer(&ifmodemode)),
)
if errno != 0 {
return nil, fmt.Errorf("error %s", errno.Error())
}
tun, err := CreateTUNFromFile(tunfile)
if err == nil && name == "tun" {
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) (TUNDevice, error) {
tun := &NativeTun{
fd: file,
events: make(chan TUNEvent, 10),
errors: make(chan error, 1),
}
name, err := tun.Name()
if err != nil {
tun.fd.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.fd.Close()
return nil, err
}
tun.rwcancel, err = rwcancel.NewRWCancel(int(file.Fd()))
if err != nil {
tun.fd.Close()
return nil, err
}
tun.routeSocket, err = unix.Socket(unix.AF_ROUTE, unix.SOCK_RAW, unix.AF_UNSPEC)
if err != nil {
tun.fd.Close()
return nil, err
}
go tun.RoutineRouteListener(tunIfindex)
// set default MTU
err = tun.setMTU(DefaultMTU)
if err != nil {
tun.Close()
return nil, err
}
return tun, nil
}
func (tun *NativeTun) Name() (string, error) {
gostat, err := tun.fd.Stat()
if err != nil {
tun.name = ""
return "", err
}
stat := gostat.Sys().(*syscall.Stat_t)
tun.name = fmt.Sprintf("tun%d", stat.Rdev%256)
return tun.name, nil
}
func (tun *NativeTun) File() *os.File {
return tun.fd
}
func (tun *NativeTun) Events() chan TUNEvent {
return tun.events
}
func (tun *NativeTun) doRead(buff []byte, offset int) (int, error) {
select {
case err := <-tun.errors:
return 0, err
default:
buff := buff[offset-4:]
n, err := tun.fd.Read(buff[:])
if n < 4 {
return 0, err
}
return n - 4, err
}
}
func (tun *NativeTun) Read(buff []byte, offset int) (int, error) {
for {
n, err := tun.doRead(buff, offset)
if err == nil || !rwcancel.ErrorIsEAGAIN(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
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.fd.Write(buff)
}
func (tun *NativeTun) Close() error {
var err3 error
err1 := tun.rwcancel.Cancel()
err2 := tun.fd.Close()
if tun.routeSocket != -1 {
unix.Shutdown(tun.routeSocket, unix.SHUT_RDWR)
err3 = unix.Close(tun.routeSocket)
tun.routeSocket = -1
} else if tun.events != nil {
close(tun.events)
}
if err1 != nil {
return err1
}
if err2 != nil {
return err2
}
return err3
}
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 ifreq_mtu
copy(ifr.Name[:], tun.name)
ifr.MTU = uint32(n)
_, _, errno := unix.Syscall(
unix.SYS_IOCTL,
uintptr(fd),
uintptr(unix.SIOCSIFMTU),
uintptr(unsafe.Pointer(&ifr)),
)
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 ifreq_mtu
copy(ifr.Name[:], tun.name)
_, _, errno := unix.Syscall(
unix.SYS_IOCTL,
uintptr(fd),
uintptr(unix.SIOCGIFMTU),
uintptr(unsafe.Pointer(&ifr)),
)
if errno != 0 {
return 0, fmt.Errorf("failed to get MTU on %s", tun.name)
}
// convert result to signed 32-bit int
mtu := ifr.MTU
if mtu >= (1 << 31) {
return int(mtu-(1<<31)) - (1 << 31), nil
}
return int(mtu), nil
}

2
uapi_bsd.go
View file

@ -1,4 +1,4 @@
// +build darwin freebsd
// +build darwin freebsd openbsd
/* SPDX-License-Identifier: GPL-2.0
*