net: move network-related files to src/net

Some namespaces are changed:

* ndn::util::FaceUri is now ndn::FaceUri
* ndn::util::ethernet is now ndn::ethernet
* ndn::util::NetworkMonitor and related classes are now in ndn::net

refs #3940

Change-Id: Ia4754caef9726efc73f5a303cec46fc95c744d70
diff --git a/tests/unit-tests/net/network-configuration-detector.cpp b/tests/unit-tests/net/network-configuration-detector.cpp
new file mode 100644
index 0000000..9aa196b
--- /dev/null
+++ b/tests/unit-tests/net/network-configuration-detector.cpp
@@ -0,0 +1,87 @@
+/* -*- 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.
+ */
+
+#include "network-configuration-detector.hpp"
+
+#include <boost/asio/ip/address.hpp>
+#include <boost/asio/ip/udp.hpp>
+#include <boost/asio/ip/basic_resolver.hpp>
+#include <boost/asio/io_service.hpp>
+#include <boost/range/iterator_range_core.hpp>
+
+namespace ndn {
+namespace tests {
+
+bool NetworkConfigurationDetector::m_isInitialized = false;
+bool NetworkConfigurationDetector::m_hasIpv4 = false;
+bool NetworkConfigurationDetector::m_hasIpv6 = false;
+
+bool
+NetworkConfigurationDetector::hasIpv4()
+{
+  if (!m_isInitialized) {
+    detect();
+  }
+  return m_hasIpv4;
+}
+
+bool
+NetworkConfigurationDetector::hasIpv6()
+{
+  if (!m_isInitialized) {
+    detect();
+  }
+  return m_hasIpv6;
+}
+
+void
+NetworkConfigurationDetector::detect()
+{
+  typedef boost::asio::ip::basic_resolver<boost::asio::ip::udp> BoostResolver;
+
+  boost::asio::io_service ioService;
+  BoostResolver resolver(ioService);
+
+  // The specified hostname must contain both A and AAAA records
+  BoostResolver::query query("a.root-servers.net", "");
+
+  boost::system::error_code errorCode;
+  BoostResolver::iterator begin = resolver.resolve(query, errorCode);
+  if (errorCode) {
+    m_isInitialized = true;
+    return;
+  }
+  BoostResolver::iterator end;
+
+  for (const auto& i : boost::make_iterator_range(begin, end)) {
+    if (i.endpoint().address().is_v4()) {
+      m_hasIpv4 = true;
+    }
+    else if (i.endpoint().address().is_v6()) {
+      m_hasIpv6 = true;
+    }
+  }
+
+  m_isInitialized = true;
+}
+
+} // namespace tests
+} // namespace ndn