face: reserved FaceIds and NullFace

refs #1620, #1622

Change-Id: I315ae262c7e0813a64b69d3e7d67de61b7b88c55
diff --git a/daemon/face/face.hpp b/daemon/face/face.hpp
index 2db2c6a..52c0894 100644
--- a/daemon/face/face.hpp
+++ b/daemon/face/face.hpp
@@ -40,8 +40,20 @@
  */
 typedef int FaceId;
 
+/// indicates an invalid FaceId
 const FaceId INVALID_FACEID = -1;
 
+/// identifies the InternalFace used in management
+const FaceId FACEID_INTERNAL_FACE = 1;
+/// identifies a packet comes from the ContentStore, in LocalControlHeader incomingFaceId
+const FaceId FACEID_CONTENT_STORE = 254;
+/// identifies the NullFace that drops every packet
+const FaceId FACEID_NULL = 255;
+/// upper bound of reserved FaceIds
+const FaceId FACEID_RESERVED_MAX = 255;
+
+
+/// pratical limit of packet size in octets
 const size_t MAX_NDN_PACKET_SIZE = 8800;
 
 
diff --git a/daemon/face/null-face.cpp b/daemon/face/null-face.cpp
new file mode 100644
index 0000000..5d55693
--- /dev/null
+++ b/daemon/face/null-face.cpp
@@ -0,0 +1,54 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014,  Regents of the University of California,
+ *                      Arizona Board of Regents,
+ *                      Colorado State University,
+ *                      University Pierre & Marie Curie, Sorbonne University,
+ *                      Washington University in St. Louis,
+ *                      Beijing Institute of Technology,
+ *                      The University of Memphis
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "null-face.hpp"
+
+namespace nfd {
+
+// FIB might restrict creating a nexthop record toward non-local face in /localhost namespace.
+// NullFace has isLocal=true to enable creating a "blackhole" FIB entry under /localhost.
+
+NullFace::NullFace(const FaceUri& uri)
+  : Face(uri, uri, true)
+{
+}
+
+void
+NullFace::sendInterest(const Interest& interest)
+{
+}
+
+void
+NullFace::sendData(const Data& data)
+{
+}
+
+void
+NullFace::close()
+{
+  this->fail("close");
+}
+
+} // namespace nfd
diff --git a/daemon/face/null-face.hpp b/daemon/face/null-face.hpp
new file mode 100644
index 0000000..3dae571
--- /dev/null
+++ b/daemon/face/null-face.hpp
@@ -0,0 +1,60 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014,  Regents of the University of California,
+ *                      Arizona Board of Regents,
+ *                      Colorado State University,
+ *                      University Pierre & Marie Curie, Sorbonne University,
+ *                      Washington University in St. Louis,
+ *                      Beijing Institute of Technology,
+ *                      The University of Memphis
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef NFD_DAEMON_FACE_NULL_FACE_HPP
+#define NFD_DAEMON_FACE_NULL_FACE_HPP
+
+#include "face.hpp"
+
+namespace nfd {
+
+/**
+ * \brief a Face that has no underlying transport and drops every packet
+ */
+class NullFace : public Face
+{
+public:
+  explicit
+  NullFace(const FaceUri& uri = FaceUri("null://"));
+
+  virtual void
+  sendInterest(const Interest& interest);
+
+  /// send a Data
+  virtual void
+  sendData(const Data& data);
+
+  /** \brief Close the face
+   *
+   *  This terminates all communication on the face and cause
+   *  onFail() method event to be invoked
+   */
+  virtual void
+  close();
+};
+
+} // namespace nfd
+
+#endif // NFD_DAEMON_FACE_NULL_FACE_HPP