fw: rename BestRouteStrategy2 class to BestRouteStrategy

Also rename ad-hoc-forwarding.t.cpp to strategy-ad-hoc-face.t.cpp
and broadcast-medium.t.cpp to strategy-broadcast-medium.t.cpp,
for consistency with the other strategy-*.t.cpp test suites.

Change-Id: Ia8f5257260563732d74c7d58e35481b73a231f06
diff --git a/daemon/fw/best-route-strategy.hpp b/daemon/fw/best-route-strategy.hpp
new file mode 100644
index 0000000..636abd2
--- /dev/null
+++ b/daemon/fw/best-route-strategy.hpp
@@ -0,0 +1,82 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2021,  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_FW_BEST_ROUTE_STRATEGY_HPP
+#define NFD_DAEMON_FW_BEST_ROUTE_STRATEGY_HPP
+
+#include "strategy.hpp"
+#include "process-nack-traits.hpp"
+#include "retx-suppression-exponential.hpp"
+
+namespace nfd {
+namespace fw {
+
+/** \brief Best Route strategy
+ *
+ *  This strategy forwards a new Interest to the lowest-cost nexthop (except downstream).
+ *  After that, if consumer retransmits the Interest (and is not suppressed according to
+ *  exponential backoff algorithm), the strategy forwards the Interest again to
+ *  the lowest-cost nexthop (except downstream) that is not previously used.
+ *  If all nexthops have been used, the strategy starts over with the first nexthop.
+ *
+ *  This strategy returns Nack to all downstreams with reason NoRoute
+ *  if there is no usable nexthop, which may be caused by:
+ *  (a) the FIB entry contains no nexthop;
+ *  (b) the FIB nexthop happens to be the sole downstream;
+ *  (c) the FIB nexthops violate scope.
+ *
+ *  This strategy returns Nack to all downstreams if all upstreams have returned Nacks.
+ *  The reason of the sent Nack equals the least severe reason among received Nacks.
+ */
+class BestRouteStrategy : public Strategy
+                        , public ProcessNackTraits<BestRouteStrategy>
+{
+public:
+  explicit
+  BestRouteStrategy(Forwarder& forwarder, const Name& name = getStrategyName());
+
+  static const Name&
+  getStrategyName();
+
+  void
+  afterReceiveInterest(const FaceEndpoint& ingress, const Interest& interest,
+                       const shared_ptr<pit::Entry>& pitEntry) override;
+
+  void
+  afterReceiveNack(const FaceEndpoint& ingress, const lp::Nack& nack,
+                   const shared_ptr<pit::Entry>& pitEntry) override;
+
+NFD_PUBLIC_WITH_TESTS_ELSE_PRIVATE:
+  static const time::milliseconds RETX_SUPPRESSION_INITIAL;
+  static const time::milliseconds RETX_SUPPRESSION_MAX;
+  RetxSuppressionExponential m_retxSuppression;
+
+  friend ProcessNackTraits<BestRouteStrategy>;
+};
+
+} // namespace fw
+} // namespace nfd
+
+#endif // NFD_DAEMON_FW_BEST_ROUTE_STRATEGY_HPP