tools: Refactoring ndn-autoconfig implementation

Change-Id: Ib92942ba40f04aaee83479177b9ba5d32a09af04
Refs: #2421
diff --git a/tools/ndn-autoconfig/guess-from-search-domains.hpp b/tools/ndn-autoconfig/guess-from-search-domains.hpp
new file mode 100644
index 0000000..e2eaa5a
--- /dev/null
+++ b/tools/ndn-autoconfig/guess-from-search-domains.hpp
@@ -0,0 +1,67 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2015,  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_TOOLS_NDN_AUTOCONFIG_GUESS_FROM_SEARCH_DOMAINS_HPP
+#define NFD_TOOLS_NDN_AUTOCONFIG_GUESS_FROM_SEARCH_DOMAINS_HPP
+
+#include "base-dns.hpp"
+
+namespace ndn {
+namespace tools {
+namespace autoconfig {
+
+/**
+ * @brief Guessing home router based on DNS query with default suffix
+ *
+ * - Request
+ *
+ *     The end host sends a DNS query that is equivalent to this command:
+ *
+ *         dig +search +short +cmd +tries=2 +ndots=10 _ndn._udp srv
+ *
+ * - Response
+ *
+ *     The DNS server should answer with an SRV record that contains the hostname and UDP port
+ *     number of the NDN router.
+ */
+class GuessFromSearchDomains : public BaseDns
+{
+public:
+  /**
+   * @brief Create stage to guess home router based on DNS query with default suffix
+   * @sa Base::Base
+   */
+  GuessFromSearchDomains(Face& face, KeyChain& keyChain,
+                         const NextStageCallback& nextStageOnFailure);
+
+  virtual void
+  start() DECL_OVERRIDE;
+};
+
+} // namespace autoconfig
+} // namespace tools
+} // namespace ndn
+
+#endif // NFD_TOOLS_NDN_AUTOCONFIG_GUESSING_FROM_SEARCH_DOMAINS_HPP