Feb 28, 2025 · Feb 28, 2025
diff --git a/vpn/tun_windows.go b/vpn/tun_windows.go
 "github.com/coder/retry"
 )

 const tunName = "Coder"
 const (
 tunName = "Coder"
 tunGUID = "{0ed1515d-04a4-4c46-abae-11ad07cf0e6d}"

 wintunDLL = "wintun.dll"
 )

 func GetNetworkingStack(t *Tunnel, _ *StartRequest, logger slog.Logger) (NetworkStack, error) {
 // Initialize COM process-wide so Tailscale can make calls to the windows

 // Set the name and GUID for the TUN interface.
 tun.WintunTunnelType = tunName
 guid, err := windows.GUIDFromString("{0ed1515d-04a4-4c46-abae-11ad07cf0e6d}")
 guid, err := windows.GUIDFromString(tunGUID)
 if err != nil {
 panic(err)
 return NetworkStack{}, xerrors.Errorf("could not parse GUID %q: %w", tunGUID,err)
 }
 tun.WintunStaticRequestedGUID = &guid

 // Ensure wintun.dll is available, and fail early if it's not to avoid
 // hanging for 5 minutes in tstunNewWithWindowsRetries.
 //
 // First, we call wintun.Version() to make the wintun package attempt to
 // load wintun.dll. This allows the wintun package to set the logging
 // callback in the DLL before we load it ourselves.
 _ = wintun.Version()

 // Then, we try to load wintun.dll ourselves so we get a better error
 // message if there was a problem. This call matches the wintun package, so
 // we're loading it in the same way.
 //
 // Note: this leaks the handle to wintun.dll, but since it's already loaded
 // it wouldn't be freed anyways.
 const (
 LOAD_LIBRARY_SEARCH_APPLICATION_DIR = 0x00000200
 LOAD_LIBRARY_SEARCH_SYSTEM32        = 0x00000800
 )
 _, err = windows.LoadLibraryEx(wintunDLL, 0, LOAD_LIBRARY_SEARCH_APPLICATION_DIR|LOAD_LIBRARY_SEARCH_SYSTEM32)
 if err != nil {
 return NetworkStack{}, xerrors.Errorf("could not load %q, it should be in the same directory as the executable (in Coder Desktop, this should have been installed automatically): %w", wintunDLL, err)
 }

 tunDev, tunName, err := tstunNewWithWindowsRetries(tailnet.Logger(logger.Named("net.tun.device")), tunName)
 if err != nil {
 return NetworkStack{}, xerrors.Errorf("create tun device: %w", err)
Original file line number	Diff line number	Diff line change
Expand Up		@@ -25,7 +25,12 @@ import (
		"github.com/coder/retry"
		)

		const tunName = "Coder"
		const (
		tunName = "Coder"
		tunGUID = "{0ed1515d-04a4-4c46-abae-11ad07cf0e6d}"

		wintunDLL = "wintun.dll"
		)

		func GetNetworkingStack(t Tunnel, _ StartRequest, logger slog.Logger) (NetworkStack, error) {
		// Initialize COM process-wide so Tailscale can make calls to the windows
Expand All		@@ -44,12 +49,35 @@ func GetNetworkingStack(t Tunnel, _ StartRequest, logger slog.Logger) (Network

		// Set the name and GUID for the TUN interface.
		tun.WintunTunnelType = tunName
		guid, err := windows.GUIDFromString("{0ed1515d-04a4-4c46-abae-11ad07cf0e6d}")
		guid, err := windows.GUIDFromString(tunGUID)
		if err != nil {
		panic(err)
		return NetworkStack{}, xerrors.Errorf("could not parse GUID %q: %w", tunGUID,err)
		}
		tun.WintunStaticRequestedGUID = &guid

		// Ensure wintun.dll is available, and fail early if it's not to avoid
		// hanging for 5 minutes in tstunNewWithWindowsRetries.
		//
		// First, we call wintun.Version() to make the wintun package attempt to
		// load wintun.dll. This allows the wintun package to set the logging
		// callback in the DLL before we load it ourselves.
		_ = wintun.Version()

		// Then, we try to load wintun.dll ourselves so we get a better error
		// message if there was a problem. This call matches the wintun package, so
		// we're loading it in the same way.
		//
		// Note: this leaks the handle to wintun.dll, but since it's already loaded
		// it wouldn't be freed anyways.
		const (
		LOAD_LIBRARY_SEARCH_APPLICATION_DIR = 0x00000200
		LOAD_LIBRARY_SEARCH_SYSTEM32 = 0x00000800
		)
		_, err = windows.LoadLibraryEx(wintunDLL, 0, LOAD_LIBRARY_SEARCH_APPLICATION_DIR\|LOAD_LIBRARY_SEARCH_SYSTEM32)
		if err != nil {
		return NetworkStack{}, xerrors.Errorf("could not load %q, it should be in the same directory as the executable (in Coder Desktop, this should have been installed automatically): %w", wintunDLL, err)
		}

		tunDev, tunName, err := tstunNewWithWindowsRetries(tailnet.Logger(logger.Named("net.tun.device")), tunName)
		if err != nil {
		return NetworkStack{}, xerrors.Errorf("create tun device: %w", err)
Expand Down