Move the "is the network disabled?" functions out of router.c

Since this is completely core functionality, I'm putting it in
core/mainloop, even though it depends on feature/hibernate. We'll
have to sort that out in the future.

src/core/mainloop/netstatus.c

@@ -0,0 +1,28 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "core/or/or.h"
+#include "core/mainloop/netstatus.h"
+#include "app/config/config.h"
+#include "feature/hibernate/hibernate.h"
+
+/** Return true iff our network is in some sense disabled or shutting down:
+ * either we're hibernating, entering hibernation, or the network is turned
+ * off with DisableNetwork. */
+int
+net_is_disabled(void)
+{
+  return get_options()->DisableNetwork || we_are_hibernating();
+}
+
+/** Return true iff our network is in some sense "completely disabled" either
+ * we're fully hibernating or the network is turned off with
+ * DisableNetwork. */
+int
+net_is_completely_disabled(void)
+{
+  return get_options()->DisableNetwork || we_are_fully_hibernating();
+}

src/core/mainloop/netstatus.h

@@ -0,0 +1,13 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_NETSTATUS_H
+#define TOR_NETSTATUS_H
+
+int net_is_disabled(void);
+int net_is_completely_disabled(void);
+
+#endif