fallback on windows

generic/rawcopy_windows.go

@@ -5,72 +5,10 @@ package generic
 import (
 	"io"
 	"net"
-	"syscall"
 )
 
 func rawCopy(dst io.Writer, src *net.TCPConn, ctrl *CopyControl) (written int64, err error) {
-	c, err := src.SyscallConn()
-	if err != nil {
-		return 0, err
-	}
-
-	buf := ctrl.Buffer
-	var locked bool
-	for {
-		var er error
-		var nr int
-		rr := c.Read(func(s uintptr) bool {
-			ctrl.Lock()
-			locked = true
-			var read uint32
-			var flags uint32
-			var wsabuf syscall.WSABuf
-			wsabuf.Buf = &buf[0]
-			wsabuf.Len = uint32(len(buf))
-			er = syscall.WSARecv(syscall.Handle(s), &wsabuf, 1, &read, &flags, nil, nil)
-			nr = int(read)
-			return true
-		})
-
-		// read EOF
-		if nr == 0 && er == nil {
-			break
-		}
-
-		if nr > 0 {
-			nw, ew := dst.Write(buf[0:nr])
-			ctrl.Unlock()
-			locked = false
-
-			if nw > 0 {
-				written += int64(nw)
-			}
-			if ew != nil {
-				err = ew
-				break
-			}
-			if nr != nw {
-				err = io.ErrShortWrite
-				break
-			}
-		}
-		if er != nil {
-			if er != io.EOF {
-				err = er
-			}
-			break
-		}
-		if rr != nil {
-			if rr != io.EOF {
-				err = rr
-			}
-			break
-		}
-	}
-
-	if locked {
-		ctrl.Unlock()
-	}
-
-	return written, err
+	// fallback to standard io.CopyBuffer
+	buf := make([]byte, bufSize)
+	return io.CopyBuffer(dst, src, buf)
 }