154 lines
3.3 KiB
Go
154 lines
3.3 KiB
Go
package nebula
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import (
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"crypto"
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"fmt"
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"io"
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"net"
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"unsafe"
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"github.com/slackhq/nebula/wintun"
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"golang.org/x/sys/windows"
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"golang.zx2c4.com/wireguard/windows/tunnel/winipcfg"
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)
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const tunGUIDLabel = "Fixed Nebula Windows GUID v1"
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type WinTun struct {
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Device string
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Cidr *net.IPNet
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MTU int
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UnsafeRoutes []route
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tun *wintun.NativeTun
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}
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func generateGUIDByDeviceName(name string) (*windows.GUID, error) {
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// GUID is 128 bit
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hash := crypto.MD5.New()
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_, err := hash.Write([]byte(tunGUIDLabel))
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if err != nil {
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return nil, err
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}
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_, err = hash.Write([]byte(name))
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if err != nil {
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return nil, err
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}
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sum := hash.Sum(nil)
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return (*windows.GUID)(unsafe.Pointer(&sum[0])), nil
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}
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func newWinTun(deviceName string, cidr *net.IPNet, defaultMTU int, unsafeRoutes []route, txQueueLen int) (ifce *WinTun, err error) {
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guid, err := generateGUIDByDeviceName(deviceName)
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if err != nil {
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return nil, fmt.Errorf("Generate GUID failed: %w", err)
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}
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tunDevice, err := wintun.CreateTUNWithRequestedGUID(deviceName, guid, defaultMTU)
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if err != nil {
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return nil, fmt.Errorf("Create TUN device failed: %w", err)
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}
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ifce = &WinTun{
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Device: deviceName,
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Cidr: cidr,
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MTU: defaultMTU,
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UnsafeRoutes: unsafeRoutes,
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tun: tunDevice.(*wintun.NativeTun),
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}
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return ifce, nil
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}
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func (c *WinTun) Activate() error {
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luid := winipcfg.LUID(c.tun.LUID())
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if err := luid.SetIPAddresses([]net.IPNet{*c.Cidr}); err != nil {
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return fmt.Errorf("failed to set address: %w", err)
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}
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foundDefault4 := false
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routes := make([]*winipcfg.RouteData, 0, len(c.UnsafeRoutes)+1)
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for _, r := range c.UnsafeRoutes {
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if !foundDefault4 {
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if cidr, bits := r.route.Mask.Size(); cidr == 0 && bits != 0 {
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foundDefault4 = true
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}
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}
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// Add our unsafe route
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routes = append(routes, &winipcfg.RouteData{
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Destination: *r.route,
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NextHop: *r.via,
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Metric: uint32(r.metric),
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})
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}
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if err := luid.AddRoutes(routes); err != nil {
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return fmt.Errorf("failed to add routes: %w", err)
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}
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ipif, err := luid.IPInterface(windows.AF_INET)
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if err != nil {
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return fmt.Errorf("failed to get ip interface: %w", err)
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}
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ipif.NLMTU = uint32(c.MTU)
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if foundDefault4 {
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ipif.UseAutomaticMetric = false
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ipif.Metric = 0
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}
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if err := ipif.Set(); err != nil {
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return fmt.Errorf("failed to set ip interface: %w", err)
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}
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return nil
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}
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func (c *WinTun) CidrNet() *net.IPNet {
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return c.Cidr
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}
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func (c *WinTun) DeviceName() string {
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return c.Device
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}
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func (c *WinTun) Read(b []byte) (int, error) {
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return c.tun.Read(b, 0)
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}
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func (c *WinTun) Write(b []byte) (int, error) {
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return c.tun.Write(b, 0)
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}
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func (c *WinTun) WriteRaw(b []byte) error {
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_, err := c.Write(b)
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return err
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}
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func (c *WinTun) NewMultiQueueReader() (io.ReadWriteCloser, error) {
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return nil, fmt.Errorf("TODO: multiqueue not implemented for windows")
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}
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func (c *WinTun) Close() error {
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// It seems that the Windows networking stack doesn't like it when we destroy interfaces that have active routes,
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// so to be certain, just remove everything before destroying.
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luid := winipcfg.LUID(c.tun.LUID())
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_ = luid.FlushRoutes(windows.AF_INET)
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_ = luid.FlushIPAddresses(windows.AF_INET)
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/* We don't support IPV6 yet
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_ = luid.FlushRoutes(windows.AF_INET6)
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_ = luid.FlushIPAddresses(windows.AF_INET6)
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*/
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_ = luid.FlushDNS(windows.AF_INET)
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return c.tun.Close()
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}
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