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tailscale/wgengine/router/dns/manager_windows.go

112 lines
2.9 KiB
Go

// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package dns
import (
"fmt"
"os/exec"
"strings"
"syscall"
"github.com/tailscale/wireguard-go/tun"
"golang.org/x/sys/windows/registry"
"tailscale.com/types/logger"
)
const (
ipv4RegBase = `SYSTEM\CurrentControlSet\Services\Tcpip\Parameters`
ipv6RegBase = `SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters`
tsRegBase = `SOFTWARE\Tailscale IPN`
)
type windowsManager struct {
logf logger.Logf
guid string
}
func newManager(mconfig ManagerConfig) managerImpl {
return windowsManager{
logf: mconfig.Logf,
guid: tun.WintunGUID,
}
}
func setRegistryString(path, name, value string) error {
key, err := registry.OpenKey(registry.LOCAL_MACHINE, path, registry.SET_VALUE)
if err != nil {
return fmt.Errorf("opening %s: %w", path, err)
}
defer key.Close()
err = key.SetStringValue(name, value)
if err != nil {
return fmt.Errorf("setting %s[%s]: %w", path, name, err)
}
return nil
}
func (m windowsManager) setNameservers(basePath string, nameservers []string) error {
path := fmt.Sprintf(`%s\Interfaces\%s`, basePath, m.guid)
value := strings.Join(nameservers, ",")
return setRegistryString(path, "NameServer", value)
}
func (m windowsManager) setDomains(basePath string, domains []string) error {
path := fmt.Sprintf(`%s\Interfaces\%s`, basePath, m.guid)
value := strings.Join(domains, ",")
return setRegistryString(path, "SearchList", value)
}
func (m windowsManager) Up(config Config) error {
var ipsv4 []string
var ipsv6 []string
for _, ip := range config.Nameservers {
if ip.Is4() {
ipsv4 = append(ipsv4, ip.String())
} else {
ipsv6 = append(ipsv6, ip.String())
}
}
if err := m.setNameservers(ipv4RegBase, ipsv4); err != nil {
return err
}
if err := m.setDomains(ipv4RegBase, config.Domains); err != nil {
return err
}
if err := m.setNameservers(ipv6RegBase, ipsv6); err != nil {
return err
}
if err := m.setDomains(ipv6RegBase, config.Domains); err != nil {
return err
}
newSearchList := strings.Join(config.Domains, ",")
if err := setRegistryString(tsRegBase, "SearchList", newSearchList); err != nil {
return err
}
// Force DNS re-registration in Active Directory. What we actually
// care about is that this command invokes the undocumented hidden
// function that forces Windows to notice that adapter settings
// have changed, which makes the DNS settings actually take
// effect.
//
// This command can take a few seconds to run.
cmd := exec.Command("ipconfig", "/registerdns")
cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}
if err := cmd.Run(); err != nil {
return fmt.Errorf("running ipconfig /registerdns: %w", err)
}
return nil
}
func (m windowsManager) Down() error {
return m.Up(Config{Nameservers: nil, Domains: nil})
}