Serve other routers' certificate and LSA

refs #4448, #4430

Change-Id: I3a9a9ae613770774be06effe26dfb866ea49f05a
diff --git a/src/lsa-segment-storage.hpp b/src/lsa-segment-storage.hpp
new file mode 100644
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+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2018,  The University of Memphis,
+ *                           Regents of the University of California,
+ *                           Arizona Board of Regents.
+ *
+ * This file is part of NLSR (Named-data Link State Routing).
+ * See AUTHORS.md for complete list of NLSR authors and contributors.
+ *
+ * NLSR 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.
+ *
+ * NLSR 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
+ * NLSR, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+#ifndef NLSR_LSA_SEGMENT_STORAGE_HPP
+#define NLSR_LSA_SEGMENT_STORAGE_HPP
+
+#include "test-access-control.hpp"
+
+#include <ndn-cxx/util/segment-fetcher.hpp>
+#include <ndn-cxx/util/signal.hpp>
+#include <ndn-cxx/util/time.hpp>
+
+#include <vector>
+#include <tuple>
+
+namespace nlsr {
+
+class LsaSegmentStorage
+{
+public:
+  LsaSegmentStorage(ndn::Scheduler& scheduler,
+                    const ndn::time::seconds lsaDeletionTimepoint);
+
+  /*! \brief Get connected to the signal emitted by SegmentFetcher
+   * \param fetcher The SegmentFetcher to whose signal LsaSegmentStorage will subscribe to.
+   */
+  void
+  connectToFetcher(ndn::util::SegmentFetcher& fetcher);
+
+  /*! \brief Returns an LSA segment for an interest from LsaSegmentStorage
+   * \param interest Interest corresponding to the returned LSA segment.
+   */
+  const ndn::Data*
+  getLsaSegment(const ndn::Interest& interest);
+
+  /*! \brief Inserts an LSA segment into LsaSegmentStorage
+   * \param segmentKey Name of data without the version number.
+   * The format of the key is /router-prefix/LS type/sequence no./segment no.
+   * \param segmentValue The actual data packet.
+   */
+  void
+  insertSegment(const ndn::Name& segmentKey, const ndn::Data& segmentValue);
+
+  /*! \brief Given the key remove the corresponding data packet from LsaSegmentStorage.
+   * \param segmentKey Key of the Data packet that will be deleted.
+   */
+  void
+  deleteSegment(const ndn::Name& segmentKey);
+
+PUBLIC_WITH_TESTS_ELSE_PRIVATE:
+  /*! \brief Callback when SegmentFetcher retrieves a segment.
+   */
+   void
+   afterFetcherSignalEmitted(const ndn::Data& lsaSegment);
+
+private:
+  /*! \brief Given an LSA name check whether Data for the same name exists in the
+   * LsaSegmentStorage. If the matched LSA data are of a lower sequence number,
+   * then remove them from LsaSegmentStorage.
+   * \param newLsaName Name of the LSA that will be matched against
+   */
+  void
+  deleteOldLsas(const ndn::Name& newLsaName);
+
+  /*! \brief Schedules the deletion of a LSA data given the segmentKey
+   */
+  void
+  scheduleLsaSegmentDeletion(const ndn::Name& segmentKey);
+
+
+private:
+  ndn::Scheduler& m_scheduler;
+
+  // Key: /<router-prefix>/<LS type>/<sequence no.>/<segment no.>
+  // Value: corresponding LSA data packet
+  //        Data name: /<router-prefix>/<LS type>/<sequence no.>/<version no.>/<segment no.>
+  std::unordered_map<ndn::Name, ndn::Data> m_lsaSegments;
+
+  const ndn::time::seconds m_lsaDeletionTimepoint;
+};
+
+} // namespace nlsr
+
+#endif // NLSR_LSA_SEGMENT_STORAGE_HPP
\ No newline at end of file