face: NDNLPv2 fragmentation and reassembly
refs #3171
Change-Id: If29035b697b904ee49cb86d9248be488657c6f9e
diff --git a/daemon/face/lp-reassembler.hpp b/daemon/face/lp-reassembler.hpp
new file mode 100644
index 0000000..fd0d874
--- /dev/null
+++ b/daemon/face/lp-reassembler.hpp
@@ -0,0 +1,160 @@
+/* -*- 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_DAEMON_FACE_LP_REASSEMBLER_HPP
+#define NFD_DAEMON_FACE_LP_REASSEMBLER_HPP
+
+#include "core/scheduler.hpp"
+#include "face-log.hpp"
+#include "transport.hpp"
+
+#include <ndn-cxx/lp/packet.hpp>
+
+namespace nfd {
+namespace face {
+
+class LinkService;
+
+/** \brief reassembles fragmented network-layer packets
+ * \sa http://redmine.named-data.net/projects/nfd/wiki/NDNLPv2
+ */
+class LpReassembler : noncopyable
+{
+public:
+ /** \brief Options that control the behavior of LpReassembler
+ */
+ class Options
+ {
+ public:
+ Options();
+
+ public:
+ /** \brief maximum number of fragments in a packet
+ *
+ * LpPackets with FragCount over this limit are dropped.
+ */
+ size_t nMaxFragments;
+
+ /** \brief timeout before a partially reassembled packet is dropped
+ */
+ time::nanoseconds reassemblyTimeout;
+ };
+
+ explicit
+ LpReassembler(const Options& options = Options(), const LinkService* linkService = nullptr);
+
+ /** \brief set options for reassembler
+ */
+ void
+ setOptions(const Options& options);
+
+ /** \return LinkService that owns this instance
+ *
+ * This is only used for logging, and may be nullptr.
+ */
+ const LinkService*
+ getLinkService() const;
+
+ /** \brief adds received fragment to buffer
+ * \param remoteEndpoint endpoint whose sends the packet
+ * \param packet received fragment;
+ * must have Fragment field
+ * \return whether network-layer packet has been completely received,
+ * the reassembled network-layer packet,
+ * and the first fragment for inspecting other NDNLPv2 headers
+ * \throw tlv::Error packet is malformed
+ */
+ std::tuple<bool, Block, lp::Packet>
+ receiveFragment(Transport::EndpointId remoteEndpoint, const lp::Packet& packet);
+
+ /** \brief count of partial packets
+ */
+ size_t
+ size() const;
+
+ /** \brief signals before a partial packet is dropped due to timeout
+ *
+ * If a partial packet is incomplete and no new fragment is received
+ * within Options::reassemblyTimeout, it would be dropped due to timeout.
+ * Before it's erased, this signal is emitted with the remote endpoint,
+ * and the number of fragments being dropped.
+ */
+ signal::Signal<LpReassembler, Transport::EndpointId, size_t> beforeTimeout;
+
+private:
+ /** \brief holds all fragments of packet until reassembled
+ */
+ struct PartialPacket
+ {
+ std::vector<lp::Packet> fragments;
+ size_t fragCount; ///< total fragments
+ size_t nReceivedFragments; ///< number of received fragments
+ scheduler::ScopedEventId dropTimer;
+ };
+
+ /** \brief index key for PartialPackets
+ */
+ typedef std::tuple<
+ Transport::EndpointId, // remoteEndpoint
+ lp::Sequence // message identifier (sequence of the first fragment)
+ > Key;
+
+ Block
+ doReassembly(const Key& key);
+
+ void
+ timeoutPartialPacket(const Key& key);
+
+private:
+ Options m_options;
+ std::map<Key, PartialPacket> m_partialPackets;
+ const LinkService* m_linkService;
+};
+
+std::ostream&
+operator<<(std::ostream& os, const FaceLogHelper<LpReassembler>& flh);
+
+inline void
+LpReassembler::setOptions(const Options& options)
+{
+ m_options = options;
+}
+
+inline const LinkService*
+LpReassembler::getLinkService() const
+{
+ return m_linkService;
+}
+
+inline size_t
+LpReassembler::size() const
+{
+ return m_partialPackets.size();
+}
+
+} // namespace face
+} // namespace nfd
+
+#endif // NFD_DAEMON_FACE_LP_REASSEMBLER_HPP