Configure addresses and MTUs, fix bugs

This commit is contained in:
Neil Alexander 2019-11-22 18:34:43 +00:00
parent f5517acc81
commit 235b64345e
No known key found for this signature in database
GPG Key ID: A02A2019A2BB0944
2 changed files with 197 additions and 44 deletions

View File

@ -40,8 +40,8 @@ func (w *tunWriter) _write(b []byte) {
}
})
}
if written-TUN_OFFSET_BYTES != n {
w.tun.log.Errorln("TUN iface write mismatch:", written-TUN_OFFSET_BYTES, "bytes written vs", n, "bytes given")
if written != n {
w.tun.log.Errorln("TUN iface write mismatch:", written, "bytes written vs", n, "bytes given")
}
}

View File

@ -1,70 +1,223 @@
package tuntap
import (
"bytes"
"errors"
"fmt"
"os/exec"
"log"
"net"
"runtime"
"strings"
"time"
"unsafe"
"golang.org/x/sys/windows"
wgtun "golang.zx2c4.com/wireguard/tun"
"golang.zx2c4.com/wireguard/windows/tunnel/winipcfg"
)
// This is to catch Windows platforms
// Configures the TUN adapter with the correct IPv6 address and MTU.
func (tun *TunAdapter) setup(ifname string, addr string, mtu int) error {
iface, err := wgtun.CreateTUN(ifname, mtu)
if err != nil {
panic(err)
}
tun.iface = iface
if mtu, err := iface.MTU(); err == nil {
tun.mtu = getSupportedMTU(mtu)
} else {
tun.mtu = 0
}
return tun.setupAddress(addr)
var err error
err = doAsSystem(func() {
iface, err := wgtun.CreateTUN(ifname, mtu)
if err != nil {
panic(err)
}
tun.iface = iface
if err := tun.setupAddress(addr); err != nil {
tun.log.Errorln("Failed to set up TUN address:", err)
}
if err := tun.setupMTU(getSupportedMTU(mtu)); err != nil {
tun.log.Errorln("Failed to set up TUN MTU:", err)
}
if mtu, err = iface.MTU(); err == nil {
tun.mtu = mtu
}
})
return err
}
// Sets the MTU of the TAP adapter.
func (tun *TunAdapter) setupMTU(mtu int) error {
if tun.iface == nil || tun.iface.Name() == "" {
return errors.New("Can't configure MTU as TAP adapter is not present")
if tun.iface == nil || tun.Name() == "" {
return errors.New("Can't configure MTU as TUN adapter is not present")
}
// Set MTU
cmd := exec.Command("netsh", "interface", "ipv6", "set", "subinterface",
fmt.Sprintf("interface=%s", tun.iface.Name()),
fmt.Sprintf("mtu=%d", mtu),
"store=active")
tun.log.Debugln("netsh command:", strings.Join(cmd.Args, " "))
output, err := cmd.CombinedOutput()
if err != nil {
tun.log.Errorln("Windows netsh failed:", err)
tun.log.Traceln(string(output))
return err
if intf, ok := tun.iface.(*wgtun.NativeTun); ok {
luid := winipcfg.LUID(intf.LUID())
ipfamily, err := luid.IPInterface(windows.AF_INET6)
if err != nil {
return err
}
ipfamily.NLMTU = uint32(mtu)
intf.ForceMTU(int(ipfamily.NLMTU))
ipfamily.UseAutomaticMetric = false
ipfamily.Metric = 0
ipfamily.DadTransmits = 0
ipfamily.RouterDiscoveryBehavior = winipcfg.RouterDiscoveryDisabled
if err := ipfamily.Set(); err != nil {
return err
}
}
time.Sleep(time.Second) // FIXME artifical delay to give netsh time to take effect
return nil
}
// Sets the IPv6 address of the TAP adapter.
func (tun *TunAdapter) setupAddress(addr string) error {
if tun.iface == nil || tun.iface.Name() == "" {
return errors.New("Can't configure IPv6 address as TAP adapter is not present")
if tun.iface == nil || tun.Name() == "" {
return errors.New("Can't configure IPv6 address as TUN adapter is not present")
}
// Set address
cmd := exec.Command("netsh", "interface", "ipv6", "add", "address",
fmt.Sprintf("interface=%s", tun.iface.Name()),
fmt.Sprintf("addr=%s", addr),
"store=active")
tun.log.Debugln("netsh command:", strings.Join(cmd.Args, " "))
output, err := cmd.CombinedOutput()
if err != nil {
tun.log.Errorln("Windows netsh failed:", err)
tun.log.Traceln(string(output))
return err
if intf, ok := tun.iface.(*wgtun.NativeTun); ok {
if ipaddr, ipnet, err := net.ParseCIDR(addr); err == nil {
luid := winipcfg.LUID(intf.LUID())
addresses := append([]net.IPNet{}, net.IPNet{
IP: ipaddr,
Mask: ipnet.Mask,
})
err := luid.SetIPAddressesForFamily(windows.AF_INET6, addresses)
if err == windows.ERROR_OBJECT_ALREADY_EXISTS {
cleanupAddressesOnDisconnectedInterfaces(windows.AF_INET6, addresses)
err = luid.SetIPAddressesForFamily(windows.AF_INET6, addresses)
}
if err != nil {
return err
}
} else {
return err
}
} else {
return errors.New("unable to get NativeTUN")
}
time.Sleep(time.Second) // FIXME artifical delay to give netsh time to take effect
return nil
}
/*
* doAsSystem
* SPDX-License-Identifier: LGPL-3.0
* Copyright (C) 2017-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
func doAsSystem(f func()) error {
runtime.LockOSThread()
defer func() {
windows.RevertToSelf()
runtime.UnlockOSThread()
}()
privileges := windows.Tokenprivileges{
PrivilegeCount: 1,
Privileges: [1]windows.LUIDAndAttributes{
{
Attributes: windows.SE_PRIVILEGE_ENABLED,
},
},
}
err := windows.LookupPrivilegeValue(nil, windows.StringToUTF16Ptr("SeDebugPrivilege"), &privileges.Privileges[0].Luid)
if err != nil {
return err
}
err = windows.ImpersonateSelf(windows.SecurityImpersonation)
if err != nil {
return err
}
var threadToken windows.Token
err = windows.OpenThreadToken(windows.CurrentThread(), windows.TOKEN_ADJUST_PRIVILEGES, false, &threadToken)
if err != nil {
return err
}
defer threadToken.Close()
err = windows.AdjustTokenPrivileges(threadToken, false, &privileges, uint32(unsafe.Sizeof(privileges)), nil, nil)
if err != nil {
return err
}
processes, err := windows.CreateToolhelp32Snapshot(windows.TH32CS_SNAPPROCESS, 0)
if err != nil {
return err
}
defer windows.CloseHandle(processes)
processEntry := windows.ProcessEntry32{Size: uint32(unsafe.Sizeof(windows.ProcessEntry32{}))}
pid := uint32(0)
for err = windows.Process32First(processes, &processEntry); err == nil; err = windows.Process32Next(processes, &processEntry) {
if strings.ToLower(windows.UTF16ToString(processEntry.ExeFile[:])) == "winlogon.exe" {
pid = processEntry.ProcessID
break
}
}
if pid == 0 {
return errors.New("unable to find winlogon.exe process")
}
winlogonProcess, err := windows.OpenProcess(windows.PROCESS_QUERY_INFORMATION, false, pid)
if err != nil {
return err
}
defer windows.CloseHandle(winlogonProcess)
var winlogonToken windows.Token
err = windows.OpenProcessToken(winlogonProcess, windows.TOKEN_IMPERSONATE|windows.TOKEN_DUPLICATE, &winlogonToken)
if err != nil {
return err
}
defer winlogonToken.Close()
var duplicatedToken windows.Token
err = windows.DuplicateTokenEx(winlogonToken, 0, nil, windows.SecurityImpersonation, windows.TokenImpersonation, &duplicatedToken)
if err != nil {
return err
}
defer duplicatedToken.Close()
err = windows.SetThreadToken(nil, duplicatedToken)
if err != nil {
return err
}
f()
return nil
}
/*
* cleanupAddressesOnDisconnectedInterfaces
* SPDX-License-Identifier: MIT
* Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
*/
func cleanupAddressesOnDisconnectedInterfaces(family winipcfg.AddressFamily, addresses []net.IPNet) {
if len(addresses) == 0 {
return
}
includedInAddresses := func(a net.IPNet) bool {
// TODO: this makes the whole algorithm O(n^2). But we can't stick net.IPNet in a Go hashmap. Bummer!
for _, addr := range addresses {
ip := addr.IP
if ip4 := ip.To4(); ip4 != nil {
ip = ip4
}
mA, _ := addr.Mask.Size()
mB, _ := a.Mask.Size()
if bytes.Equal(ip, a.IP) && mA == mB {
return true
}
}
return false
}
interfaces, err := winipcfg.GetAdaptersAddresses(family, winipcfg.GAAFlagDefault)
if err != nil {
return
}
for _, iface := range interfaces {
if iface.OperStatus == winipcfg.IfOperStatusUp {
continue
}
for address := iface.FirstUnicastAddress; address != nil; address = address.Next {
ip := address.Address.IP()
ipnet := net.IPNet{IP: ip, Mask: net.CIDRMask(int(address.OnLinkPrefixLength), 8*len(ip))}
if includedInAddresses(ipnet) {
log.Printf("Cleaning up stale address %s from interface %s", ipnet.String(), iface.FriendlyName())
iface.LUID.DeleteIPAddress(ipnet)
}
}
}
}