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-rw-r--r--tun_darwin.go193
1 files changed, 87 insertions, 106 deletions
diff --git a/tun_darwin.go b/tun_darwin.go
index 87f6af6..5514563 100644
--- a/tun_darwin.go
+++ b/tun_darwin.go
@@ -1,22 +1,17 @@
-/* Copyright (c) 2016, Song Gao <song@gao.io>
- * All rights reserved.
+/* SPDX-License-Identifier: GPL-2.0
*
- * Code from https://github.com/songgao/water
+ * Copyright (C) 2017-2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
package main
import (
"encoding/binary"
- "errors"
"fmt"
- "golang.org/x/net/ipv4"
"golang.org/x/net/ipv6"
"golang.org/x/sys/unix"
- "io"
"net"
"os"
- "sync"
"time"
"unsafe"
)
@@ -36,36 +31,32 @@ type sockaddrCtl struct {
scReserved [5]uint32
}
-// NativeTUN is a hack to work around the first 4 bytes "packet
+// NativeTun is a hack to work around the first 4 bytes "packet
// information" because there doesn't seem to be an IFF_NO_PI for darwin.
-type NativeTUN struct {
+type NativeTun struct {
name string
- f io.ReadWriteCloser
+ fd *os.File
mtu int
- rMu sync.Mutex
- rBuf []byte
-
- wMu sync.Mutex
- wBuf []byte
-
events chan TUNEvent
errors chan error
}
var sockaddrCtlSize uintptr = 32
-func CreateTUN(name string) (ifce TUNDevice, err error) {
+func CreateTUN(name string) (TUNDevice, error) {
ifIndex := -1
- fmt.Sscanf(name, "utun%d", &ifIndex)
- if ifIndex < 0 {
- return nil, fmt.Errorf("error parsing interface name %s, must be utun[0-9]+", name)
+ if (name != "utun") {
+ fmt.Sscanf(name, "utun%d", &ifIndex)
+ if 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, fmt.Errorf("error in unix.Socket: %v", err)
+ return nil, err
}
var ctlInfo = &struct {
@@ -83,8 +74,7 @@ func CreateTUN(name string) (ifce TUNDevice, err error) {
)
if errno != 0 {
- err = errno
- return nil, fmt.Errorf("error in unix.Syscall(unix.SYS_IOTL, ...): %v", err)
+ return nil, fmt.Errorf("_CTLIOCGINFO: %v", errno)
}
sc := sockaddrCtl{
@@ -105,148 +95,139 @@ func CreateTUN(name string) (ifce TUNDevice, err error) {
)
if errno != 0 {
- err = errno
- return nil, fmt.Errorf("error in unix.RawSyscall(unix.SYS_CONNECT, ...): %v", err)
+ return nil, fmt.Errorf("SYS_CONNECT: %v", errno)
}
- // read (new) name of interface
+ tun, err := CreateTUNFromFile(os.NewFile(uintptr(fd), ""))
- var ifName struct {
- name [16]byte
+ if err == nil && name == "utun" {
+ fmt.Printf("OS assigned interface: %s\n", tun.(*NativeTun).name)
}
- ifNameSize := uintptr(16)
- _, _, errno = unix.Syscall6(
- unix.SYS_GETSOCKOPT,
- uintptr(fd),
- 2, /* #define SYSPROTO_CONTROL 2 */
- 2, /* #define UTUN_OPT_IFNAME 2 */
- uintptr(unsafe.Pointer(&ifName)),
- uintptr(unsafe.Pointer(&ifNameSize)), 0)
+ return tun, err
+}
- if errno != 0 {
- err = errno
- return nil, fmt.Errorf("error in unix.Syscall6(unix.SYS_GETSOCKOPT, ...): %v", err)
- }
+func CreateTUNFromFile(file *os.File) (TUNDevice, error) {
- device := &NativeTUN{
- name: string(ifName.name[:ifNameSize-1 /* -1 is for \0 */]),
- f: os.NewFile(uintptr(fd), string(ifName.name[:])),
+ tun := &NativeTun{
+ fd: file,
mtu: 1500,
events: make(chan TUNEvent, 10),
errors: make(chan error, 1),
}
- // start listener
+ _, err := tun.Name()
+ if err != nil {
+ return nil, err
+ }
- go func(native *NativeTUN) {
- // TODO: Fix this very niave implementation
+ // TODO: Fix this very naive implementation
+ go func(tun *NativeTun) {
var (
statusUp bool
statusMTU int
)
for ; ; time.Sleep(time.Second) {
- intr, err := net.InterfaceByName(device.name)
+ intr, err := net.InterfaceByName(tun.name)
if err != nil {
- native.errors <- err
+ tun.errors <- err
return
}
// Up / Down event
up := (intr.Flags & net.FlagUp) != 0
if up != statusUp && up {
- native.events <- TUNEventUp
+ tun.events <- TUNEventUp
}
if up != statusUp && !up {
- native.events <- TUNEventDown
+ tun.events <- TUNEventDown
}
statusUp = up
// MTU changes
if intr.MTU != statusMTU {
- native.events <- TUNEventMTUUpdate
+ tun.events <- TUNEventMTUUpdate
}
statusMTU = intr.MTU
}
- }(device)
+ }(tun)
// set default MTU
+ err = tun.setMTU(DefaultMTU)
- err = device.setMTU(DefaultMTU)
-
- return device, err
+ return tun, err
}
-var _ io.ReadWriteCloser = (*NativeTUN)(nil)
+func (tun *NativeTun) Name() (string, error) {
-func (t *NativeTUN) Events() chan TUNEvent {
- return t.events
-}
+ var ifName struct {
+ name [16]byte
+ }
+ ifNameSize := uintptr(16)
-func (t *NativeTUN) Read(to []byte) (int, error) {
- t.rMu.Lock()
- defer t.rMu.Unlock()
+ _, _, errno := unix.Syscall6(
+ unix.SYS_GETSOCKOPT,
+ uintptr(tun.fd.Fd()),
+ 2, /* #define SYSPROTO_CONTROL 2 */
+ 2, /* #define UTUN_OPT_IFNAME 2 */
+ uintptr(unsafe.Pointer(&ifName)),
+ uintptr(unsafe.Pointer(&ifNameSize)), 0)
- if cap(t.rBuf) < len(to)+4 {
- t.rBuf = make([]byte, len(to)+4)
+ if errno != 0 {
+ return "", fmt.Errorf("SYS_GETSOCKOPT: %v", errno)
}
- t.rBuf = t.rBuf[:len(to)+4]
- n, err := t.f.Read(t.rBuf)
- copy(to, t.rBuf[4:])
- return n - 4, err
+ tun.name = string(ifName.name[:ifNameSize-1])
+ return tun.name, nil
}
-func (t *NativeTUN) Write(from []byte) (int, error) {
+func (tun *NativeTun) File() *os.File {
+ return tun.fd
+}
- if len(from) == 0 {
- return 0, unix.EIO
- }
+func (tun *NativeTun) Events() chan TUNEvent {
+ return tun.events
+}
- t.wMu.Lock()
- defer t.wMu.Unlock()
+func (tun *NativeTun) Read(buff []byte, offset int) (int, error) {
- if cap(t.wBuf) < len(from)+4 {
- t.wBuf = make([]byte, len(from)+4)
+ buff = buff[offset-4:]
+ n, err := tun.fd.Read(buff[:])
+ if n < 4 {
+ return 0, err
}
- t.wBuf = t.wBuf[:len(from)+4]
-
- // determine the IP Family for the NULL L2 Header
+ return n - 4, err
+}
- ipVer := from[0] >> 4
- if ipVer == ipv4.Version {
- t.wBuf[3] = unix.AF_INET
- } else if ipVer == ipv6.Version {
- t.wBuf[3] = unix.AF_INET6
- } else {
- return 0, errors.New("Unable to determine IP version from packet.")
- }
+func (tun *NativeTun) Write(buff []byte, offset int) (int, error) {
- copy(t.wBuf[4:], from)
+ // reserve space for header
- n, err := t.f.Write(t.wBuf)
- return n - 4, err
-}
+ buff = buff[offset-4:]
-func (t *NativeTUN) Close() error {
+ // add packet information header
- // lock to make sure no read/write is in process.
+ buff[0] = 0x00
+ buff[1] = 0x00
+ buff[2] = 0x00
- t.rMu.Lock()
- defer t.rMu.Unlock()
+ if buff[4]>>4 == ipv6.Version {
+ buff[3] = unix.AF_INET6
+ } else {
+ buff[3] = unix.AF_INET
+ }
- t.wMu.Lock()
- defer t.wMu.Unlock()
+ // write
- return t.f.Close()
+ return tun.fd.Write(buff)
}
-func (t *NativeTUN) Name() string {
- return t.name
+func (tun *NativeTun) Close() error {
+ return tun.fd.Close()
}
-func (t *NativeTUN) setMTU(n int) error {
+func (tun *NativeTun) setMTU(n int) error {
// open datagram socket
@@ -267,7 +248,7 @@ func (t *NativeTUN) setMTU(n int) error {
// do ioctl call
var ifr [32]byte
- copy(ifr[:], t.name)
+ copy(ifr[:], tun.name)
binary.LittleEndian.PutUint32(ifr[16:20], uint32(n))
_, _, errno := unix.Syscall(
unix.SYS_IOCTL,
@@ -277,13 +258,13 @@ func (t *NativeTUN) setMTU(n int) error {
)
if errno != 0 {
- return fmt.Errorf("Failed to set MTU on %s", t.name)
+ return fmt.Errorf("Failed to set MTU on %s", tun.name)
}
return nil
}
-func (t *NativeTUN) MTU() (int, error) {
+func (tun *NativeTun) MTU() (int, error) {
// open datagram socket
@@ -302,7 +283,7 @@ func (t *NativeTUN) MTU() (int, error) {
// do ioctl call
var ifr [64]byte
- copy(ifr[:], t.name)
+ copy(ifr[:], tun.name)
_, _, errno := unix.Syscall(
unix.SYS_IOCTL,
uintptr(fd),
@@ -310,7 +291,7 @@ func (t *NativeTUN) MTU() (int, error) {
uintptr(unsafe.Pointer(&ifr[0])),
)
if errno != 0 {
- return 0, fmt.Errorf("Failed to get MTU on %s", t.name)
+ return 0, fmt.Errorf("Failed to get MTU on %s", tun.name)
}
// convert result to signed 32-bit int
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.