face: allow enabling/disabling congestion marking through config file

refs #4465

Change-Id: I888b83b1fdbe8e3fc36a902bf7af52147807d829
diff --git a/daemon/face/face-system.hpp b/daemon/face/face-system.hpp
index 5ea428f..1a49fce 100644
--- a/daemon/face/face-system.hpp
+++ b/daemon/face/face-system.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2017,  Regents of the University of California,
+ * Copyright (c) 2014-2018,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -80,11 +80,19 @@
   void
   setConfigFile(ConfigFile& configFile);
 
+  /** \brief configuration options from "general" section
+   */
+  struct GeneralConfig
+  {
+    bool wantCongestionMarking = false;
+  };
+
   /** \brief context for processing a config section in ProtocolFactory
    */
   class ConfigContext : noncopyable
   {
   public:
+    GeneralConfig generalConfig;
     bool isDryRun;
   };