fw: Add Random Forwarding Strategy
Implement a forwarding strategy that chooses a random outgoing face,
excluding the incoming face of an Interest packet.
Refs: #4992
Change-Id: I056cd0f05463f5f0742c6adcb32ec1df8ef7529b
diff --git a/daemon/fw/random-strategy.cpp b/daemon/fw/random-strategy.cpp
new file mode 100644
index 0000000..a95d2cd
--- /dev/null
+++ b/daemon/fw/random-strategy.cpp
@@ -0,0 +1,92 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2019, 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/>.
+ */
+
+#include "random-strategy.hpp"
+#include "algorithm.hpp"
+
+#include <ndn-cxx/util/random.hpp>
+
+namespace nfd {
+namespace fw {
+
+NFD_REGISTER_STRATEGY(RandomStrategy);
+NFD_LOG_INIT(RandomStrategy);
+
+RandomStrategy::RandomStrategy(Forwarder& forwarder, const Name& name)
+ : Strategy(forwarder)
+ , ProcessNackTraits(this)
+{
+ ParsedInstanceName parsed = parseInstanceName(name);
+ if (!parsed.parameters.empty()) {
+ NDN_THROW(std::invalid_argument("RandomStrategy does not accept parameters"));
+ }
+ if (parsed.version && *parsed.version != getStrategyName()[-1].toVersion()) {
+ NDN_THROW(std::invalid_argument(
+ "RandomStrategy does not support version " + to_string(*parsed.version)));
+ }
+ this->setInstanceName(makeInstanceName(name, getStrategyName()));
+}
+
+const Name&
+RandomStrategy::getStrategyName()
+{
+ static Name strategyName("/localhost/nfd/strategy/random/%FD%01");
+ return strategyName;
+}
+
+void
+RandomStrategy::afterReceiveInterest(const FaceEndpoint& ingress, const Interest& interest,
+ const shared_ptr<pit::Entry>& pitEntry)
+{
+ const fib::Entry& fibEntry = this->lookupFib(*pitEntry);
+ const Face& inFace = ingress.face;
+ fib::NextHopList nhs;
+
+ std::copy_if(fibEntry.getNextHops().begin(), fibEntry.getNextHops().end(), std::back_inserter(nhs),
+ [&] (const auto& nh) { return isNextHopEligible(inFace, interest, nh, pitEntry); });
+
+ if (nhs.empty()) {
+ NFD_LOG_DEBUG(interest << " from=" << ingress << " no nexthop");
+
+ lp::NackHeader nackHeader;
+ nackHeader.setReason(lp::NackReason::NO_ROUTE);
+ this->sendNack(pitEntry, ingress, nackHeader);
+ this->rejectPendingInterest(pitEntry);
+ return;
+ }
+
+ std::shuffle(nhs.begin(), nhs.end(), ndn::random::getRandomNumberEngine());
+ this->sendInterest(pitEntry, FaceEndpoint(nhs.front().getFace(), 0), interest);
+}
+
+void
+RandomStrategy::afterReceiveNack(const FaceEndpoint& ingress, const lp::Nack& nack,
+ const shared_ptr<pit::Entry>& pitEntry)
+{
+ this->processNack(ingress.face, nack, pitEntry);
+}
+
+} // namespace fw
+} // namespace nfd
diff --git a/daemon/fw/random-strategy.hpp b/daemon/fw/random-strategy.hpp
new file mode 100644
index 0000000..6837e29
--- /dev/null
+++ b/daemon/fw/random-strategy.hpp
@@ -0,0 +1,66 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2019, 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_RANDOM_STRATEGY_HPP
+#define NFD_DAEMON_FW_RANDOM_STRATEGY_HPP
+
+#include "strategy.hpp"
+#include "process-nack-traits.hpp"
+
+namespace nfd {
+namespace fw {
+
+/** \brief Randomly chooses a nexthop
+ *
+ * Sends an incoming interest to a random outgoing face,
+ * excluding the incoming face.
+ *
+ */
+class RandomStrategy : public Strategy
+ , public ProcessNackTraits<RandomStrategy>
+{
+public:
+ explicit
+ RandomStrategy(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;
+
+private:
+ friend ProcessNackTraits<RandomStrategy>;
+};
+
+} // namespace fw
+} // namespace nfd
+
+#endif // NFD_DAEMON_FW_RANDOM_STRATEGY_HPP