tun: windows: registration of write buffer no longer required

README.md

@@ -2,8 +2,6 @@
 
 This is an implementation of WireGuard in Go.
 
-***WARNING:*** This is a work in progress and not ready for prime time, with no official "releases" yet. It is extremely rough around the edges and leaves much to be desired. There are bugs and we are not yet in a position to make claims about its security. Beware.
-
 ## Usage
 
 Most Linux kernel WireGuard users are used to adding an interface with `ip link add wg0 type wireguard`. With wireguard-go, instead simply run:

tun/tun_windows.go

@@ -11,11 +11,11 @@ import (
 	"io"
 	"os"
 	"sync"
-	"sync/atomic"
 	"time"
 	"unsafe"
 
 	"golang.org/x/sys/windows"
+
 	"golang.zx2c4.com/wireguard/tun/wintun"
 )
 
@@ -42,7 +42,6 @@ type NativeTun struct {
 	wt                        *wintun.Wintun
 	tunFileRead               *os.File
 	tunFileWrite              *os.File
-	haveRegisteredWriteBuffer int32
 	tunLock                   sync.Mutex
 	close                     bool
 	rdBuff                    *exchgBufRead
@@ -142,7 +141,6 @@ func (tun *NativeTun) openTUN() error {
 			}
 			return err
 		}
-		atomic.StoreInt32(&tun.haveRegisteredWriteBuffer, 0)
 	}
 	return nil
 }
@@ -321,15 +319,6 @@ func (tun *NativeTun) Flush() error {
 			return err
 		}
 
-		if atomic.CompareAndSwapInt32(&tun.haveRegisteredWriteBuffer, 0, 1) {
-			firstSize := (*uint32)(unsafe.Pointer(&tun.wrBuff.data[0]))
-			saved := *firstSize
-			*firstSize = 0
-			// Set the maximum buffer length with an invalid write.
-			tun.tunFileWrite.Write(tun.wrBuff.data[:])
-			*firstSize = saved
-		}
-
 		for {
 			_, err = file.Write(tun.wrBuff.data[:tun.wrBuff.offset])
 			if err != nil {