use blocking mode pre-go1.11

syscalls_linux_go1.11.go

@@ -0,0 +1,27 @@
+// +build linux,go1.11
+
+package water
+
+import (
+	"os"
+	"syscall"
+)
+
+func openDev(config Config) (ifce *Interface, err error) {
+	var fdInt int
+	if fdInt, err = syscall.Open(
+		"/dev/net/tun", os.O_RDWR|syscall.O_NONBLOCK, 0); err != nil {
+		return nil, err
+	}
+
+	name, err := setupFd(config, uintptr(fdInt))
+	if err != nil {
+		return nil, err
+	}
+
+	return &Interface{
+		isTAP:           config.DeviceType == TAP,
+		ReadWriteCloser: os.NewFile(uintptr(fdInt), "tun"),
+		name:            name,
+	}, nil
+}