base: add PacketBase to provide wrappers for congestion tags

refs #3797

Change-Id: I8747bb4fcbc11bfd1731516896b8aef1ec181c36
diff --git a/src/packet-base.hpp b/src/packet-base.hpp
new file mode 100644
index 0000000..ff76732
--- /dev/null
+++ b/src/packet-base.hpp
@@ -0,0 +1,47 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2013-2017 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ */
+
+#ifndef NDN_PACKET_BASE_HPP
+#define NDN_PACKET_BASE_HPP
+
+#include "tag-host.hpp"
+
+namespace ndn {
+
+/** \brief base class to allow simple management of packet tags
+ */
+class PacketBase : public TagHost
+{
+public:
+  /** \brief get the value of the CongestionMark tag
+   */
+  uint64_t
+  getCongestionMark() const;
+
+  /** \brief set the CongestionMark tag to the specified value
+   */
+  void
+  setCongestionMark(uint64_t mark);
+};
+
+} // namespace ndn
+
+#endif // NDN_PACKET_BASE_HPP