fw: implement self-learning forwarding strategy
refs #4279
Change-Id: I3c80820f9e3382d204a75ea3248234581b4d97d2
diff --git a/daemon/fw/forwarder.cpp b/daemon/fw/forwarder.cpp
index d55da5a..b53b82d 100644
--- a/daemon/fw/forwarder.cpp
+++ b/daemon/fw/forwarder.cpp
@@ -1,6 +1,6 @@
/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
- * Copyright (c) 2014-2018, Regents of the University of California,
+ * Copyright (c) 2014-2019, Regents of the University of California,
* Arizona Board of Regents,
* Colorado State University,
* University Pierre & Marie Curie, Sorbonne University,
@@ -515,6 +515,7 @@
void
Forwarder::setExpiryTimer(const shared_ptr<pit::Entry>& pitEntry, time::milliseconds duration)
{
+ BOOST_ASSERT(pitEntry);
BOOST_ASSERT(duration >= 0_ms);
scheduler::cancel(pitEntry->expiryTimer);
diff --git a/daemon/fw/self-learning-strategy.cpp b/daemon/fw/self-learning-strategy.cpp
new file mode 100644
index 0000000..5a43a26
--- /dev/null
+++ b/daemon/fw/self-learning-strategy.cpp
@@ -0,0 +1,249 @@
+/* -*- 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 "self-learning-strategy.hpp"
+#include "algorithm.hpp"
+
+#include "core/logger.hpp"
+#include "core/global-io.hpp"
+#include "rib/service.hpp"
+
+#include <ndn-cxx/lp/empty-value.hpp>
+#include <ndn-cxx/lp/prefix-announcement-header.hpp>
+#include <ndn-cxx/lp/tags.hpp>
+
+#include <boost/range/adaptor/reversed.hpp>
+
+namespace nfd {
+namespace fw {
+
+NFD_LOG_INIT(SelfLearningStrategy);
+NFD_REGISTER_STRATEGY(SelfLearningStrategy);
+
+const time::milliseconds SelfLearningStrategy::ROUTE_RENEW_LIFETIME(600_s);
+
+SelfLearningStrategy::SelfLearningStrategy(Forwarder& forwarder, const Name& name)
+ : Strategy(forwarder)
+{
+ ParsedInstanceName parsed = parseInstanceName(name);
+ if (!parsed.parameters.empty()) {
+ BOOST_THROW_EXCEPTION(std::invalid_argument("SelfLearningStrategy does not accept parameters"));
+ }
+ if (parsed.version && *parsed.version != getStrategyName()[-1].toVersion()) {
+ BOOST_THROW_EXCEPTION(std::invalid_argument(
+ "SelfLearningStrategy does not support version " + to_string(*parsed.version)));
+ }
+ this->setInstanceName(makeInstanceName(name, getStrategyName()));
+}
+
+const Name&
+SelfLearningStrategy::getStrategyName()
+{
+ static Name strategyName("/localhost/nfd/strategy/self-learning/%FD%01");
+ return strategyName;
+}
+
+void
+SelfLearningStrategy::afterReceiveInterest(const Face& inFace, const Interest& interest,
+ const shared_ptr<pit::Entry>& pitEntry)
+{
+ const fib::Entry& fibEntry = this->lookupFib(*pitEntry);
+ const fib::NextHopList& nexthops = fibEntry.getNextHops();
+
+ bool isNonDiscovery = interest.getTag<lp::NonDiscoveryTag>() != nullptr;
+ auto inRecordInfo = pitEntry->getInRecord(inFace)->insertStrategyInfo<InRecordInfo>().first;
+ if (isNonDiscovery) { // "non-discovery" Interest
+ inRecordInfo->isNonDiscoveryInterest = true;
+ if (nexthops.empty()) { // return NACK if no matching FIB entry exists
+ NFD_LOG_DEBUG("NACK non-discovery Interest=" << interest << " from=" << inFace.getId() << " noNextHop");
+ lp::NackHeader nackHeader;
+ nackHeader.setReason(lp::NackReason::NO_ROUTE);
+ this->sendNack(pitEntry, inFace, nackHeader);
+ this->rejectPendingInterest(pitEntry);
+ }
+ else { // multicast it if matching FIB entry exists
+ multicastInterest(interest, inFace, pitEntry, nexthops);
+ }
+ }
+ else { // "discovery" Interest
+ inRecordInfo->isNonDiscoveryInterest = false;
+ if (nexthops.empty()) { // broadcast it if no matching FIB entry exists
+ broadcastInterest(interest, inFace, pitEntry);
+ }
+ else { // multicast it with "non-discovery" mark if matching FIB entry exists
+ interest.setTag(make_shared<lp::NonDiscoveryTag>(lp::EmptyValue{}));
+ multicastInterest(interest, inFace, pitEntry, nexthops);
+ }
+ }
+}
+
+void
+SelfLearningStrategy::afterReceiveData(const shared_ptr<pit::Entry>& pitEntry,
+ const Face& inFace, const Data& data)
+{
+ OutRecordInfo* outRecordInfo = pitEntry->getOutRecord(inFace)->getStrategyInfo<OutRecordInfo>();
+ if (outRecordInfo && outRecordInfo->isNonDiscoveryInterest) { // outgoing Interest was non-discovery
+ if (!needPrefixAnn(pitEntry)) { // no need to attach a PA (common cases)
+ sendDataToAll(pitEntry, inFace, data);
+ }
+ else { // needs a PA (to respond discovery Interest)
+ asyncProcessData(pitEntry, inFace, data);
+ }
+ }
+ else { // outgoing Interest was discovery
+ auto paTag = data.getTag<lp::PrefixAnnouncementTag>();
+ if (paTag != nullptr) {
+ addRoute(pitEntry, inFace, data, *paTag->get().getPrefixAnn());
+ }
+ else { // Data contains no PrefixAnnouncement, upstreams do not support self-learning
+ }
+ sendDataToAll(pitEntry, inFace, data);
+ }
+}
+
+void
+SelfLearningStrategy::afterReceiveNack(const Face& inFace, const lp::Nack& nack,
+ const shared_ptr<pit::Entry>& pitEntry)
+{
+ NFD_LOG_DEBUG("Nack for " << nack.getInterest() << " from=" << inFace.getId() << ": " << nack.getReason());
+ if (nack.getReason() == lp::NackReason::NO_ROUTE) { // remove FIB entries
+ BOOST_ASSERT(this->lookupFib(*pitEntry).hasNextHops());
+ NFD_LOG_DEBUG("Send NACK to all downstreams");
+ this->sendNacks(pitEntry, nack.getHeader());
+ renewRoute(nack.getInterest().getName(), inFace.getId(), 0_ms);
+ }
+}
+
+void
+SelfLearningStrategy::broadcastInterest(const Interest& interest, const Face& inFace,
+ const shared_ptr<pit::Entry>& pitEntry)
+{
+ for (auto& outFace : this->getFaceTable() | boost::adaptors::reversed) {
+ if ((outFace.getId() == inFace.getId() && outFace.getLinkType() != ndn::nfd::LINK_TYPE_AD_HOC) ||
+ wouldViolateScope(inFace, interest, outFace) || outFace.getScope() == ndn::nfd::FACE_SCOPE_LOCAL) {
+ continue;
+ }
+ this->sendInterest(pitEntry, outFace, interest);
+ pitEntry->getOutRecord(outFace)->insertStrategyInfo<OutRecordInfo>().first->isNonDiscoveryInterest = false;
+ NFD_LOG_DEBUG("send discovery Interest=" << interest << " from="
+ << inFace.getId() << " to=" << outFace.getId());
+ }
+}
+
+void
+SelfLearningStrategy::multicastInterest(const Interest& interest, const Face& inFace,
+ const shared_ptr<pit::Entry>& pitEntry,
+ const fib::NextHopList& nexthops)
+{
+ for (const auto& nexthop : nexthops) {
+ Face& outFace = nexthop.getFace();
+ if ((outFace.getId() == inFace.getId() && outFace.getLinkType() != ndn::nfd::LINK_TYPE_AD_HOC) ||
+ wouldViolateScope(inFace, interest, outFace)) {
+ continue;
+ }
+ this->sendInterest(pitEntry, outFace, interest);
+ pitEntry->getOutRecord(outFace)->insertStrategyInfo<OutRecordInfo>().first->isNonDiscoveryInterest = true;
+ NFD_LOG_DEBUG("send non-discovery Interest=" << interest << " from="
+ << inFace.getId() << " to=" << outFace.getId());
+ }
+}
+
+void
+SelfLearningStrategy::asyncProcessData(const shared_ptr<pit::Entry>& pitEntry, const Face& inFace, const Data& data)
+{
+ // Given that this processing is asynchronous, the PIT entry's expiry timer is extended first
+ // to ensure that the entry will not be removed before the whole processing is finished
+ // (the PIT entry's expiry timer was set to 0 before dispatching)
+ this->setExpiryTimer(pitEntry, 1_s);
+
+ runOnRibIoService([pitEntryWeak = weak_ptr<pit::Entry>{pitEntry}, inFaceId = inFace.getId(), data, this] {
+ rib::Service::get().getRibManager().slFindAnn(data.getName(),
+ [pitEntryWeak, inFaceId, data, this] (optional<ndn::PrefixAnnouncement> paOpt) {
+ if (paOpt) {
+ runOnMainIoService([pitEntryWeak, inFaceId, data, pa = std::move(*paOpt), this] {
+ auto pitEntry = pitEntryWeak.lock();
+ auto inFace = this->getFace(inFaceId);
+ if (pitEntry && inFace) {
+ NFD_LOG_DEBUG("found PrefixAnnouncement=" << pa.getAnnouncedName());
+ data.setTag(make_shared<lp::PrefixAnnouncementTag>(lp::PrefixAnnouncementHeader(pa)));
+ this->sendDataToAll(pitEntry, *inFace, data);
+ this->setExpiryTimer(pitEntry, 0_ms);
+ }
+ else {
+ NFD_LOG_DEBUG("PIT entry or Face no longer exists");
+ }
+ });
+ }
+ });
+ });
+}
+
+bool
+SelfLearningStrategy::needPrefixAnn(const shared_ptr<pit::Entry>& pitEntry)
+{
+ bool hasDiscoveryInterest = false;
+ bool directToConsumer = true;
+
+ auto now = time::steady_clock::now();
+ for (const auto& inRecord : pitEntry->getInRecords()) {
+ if (inRecord.getExpiry() > now) {
+ InRecordInfo* inRecordInfo = inRecord.getStrategyInfo<InRecordInfo>();
+ if (inRecordInfo && !inRecordInfo->isNonDiscoveryInterest) {
+ hasDiscoveryInterest = true;
+ }
+ if (inRecord.getFace().getScope() != ndn::nfd::FACE_SCOPE_LOCAL) {
+ directToConsumer = false;
+ }
+ }
+ }
+ return hasDiscoveryInterest && !directToConsumer;
+}
+
+void
+SelfLearningStrategy::addRoute(const shared_ptr<pit::Entry>& pitEntry, const Face& inFace,
+ const Data& data, const ndn::PrefixAnnouncement& pa)
+{
+ runOnRibIoService([pitEntryWeak = weak_ptr<pit::Entry>{pitEntry}, inFaceId = inFace.getId(), data, pa] {
+ rib::Service::get().getRibManager().slAnnounce(pa, inFaceId, ROUTE_RENEW_LIFETIME,
+ [] (rib::RibManager::SlAnnounceResult res) {
+ NFD_LOG_DEBUG("Add route via PrefixAnnouncement with result=" << res);
+ });
+ });
+}
+
+void
+SelfLearningStrategy::renewRoute(const Name& name, FaceId inFaceId, time::milliseconds maxLifetime)
+{
+ // renew route with PA or ignore PA (if route has no PA)
+ runOnRibIoService([name, inFaceId, maxLifetime] {
+ rib::Service::get().getRibManager().slRenew(name, inFaceId, maxLifetime,
+ [] (rib::RibManager::SlAnnounceResult res) {
+ NFD_LOG_DEBUG("Renew route with result=" << res);
+ });
+ });
+}
+
+} // namespace fw
+} // namespace nfd
diff --git a/daemon/fw/self-learning-strategy.hpp b/daemon/fw/self-learning-strategy.hpp
new file mode 100644
index 0000000..e0c3962
--- /dev/null
+++ b/daemon/fw/self-learning-strategy.hpp
@@ -0,0 +1,148 @@
+/* -*- 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_SELF_LEARNING_STRATEGY_HPP
+#define NFD_DAEMON_FW_SELF_LEARNING_STRATEGY_HPP
+
+#include "fw/strategy.hpp"
+
+#include <ndn-cxx/lp/prefix-announcement-header.hpp>
+
+namespace nfd {
+namespace fw {
+
+/** \brief Self-learning strategy
+ *
+ * This strategy first broadcasts Interest to learn a single path towards data,
+ * then unicasts subsequent Interests along the learned path
+ *
+ * \see https://redmine.named-data.net/attachments/864/Self-learning-strategy-v1.pdf
+ */
+class SelfLearningStrategy : public Strategy
+{
+public:
+ explicit
+ SelfLearningStrategy(Forwarder& forwarder, const Name& name = getStrategyName());
+
+ static const Name&
+ getStrategyName();
+
+ /// StrategyInfo on pit::InRecord
+ class InRecordInfo : public StrategyInfo
+ {
+ public:
+ static constexpr int
+ getTypeId()
+ {
+ return 1040;
+ }
+
+ public:
+ bool isNonDiscoveryInterest = false;
+ };
+
+ /// StrategyInfo on pit::OutRecord
+ class OutRecordInfo : public StrategyInfo
+ {
+ public:
+ static constexpr int
+ getTypeId()
+ {
+ return 1041;
+ }
+
+ public:
+ bool isNonDiscoveryInterest = false;
+ };
+
+public: // triggers
+ void
+ afterReceiveInterest(const Face& inFace, const Interest& interest,
+ const shared_ptr<pit::Entry>& pitEntry) override;
+
+ void
+ afterReceiveData(const shared_ptr<pit::Entry>& pitEntry,
+ const Face& inFace, const Data& data) override;
+
+ void
+ afterReceiveNack(const Face& inFace, const lp::Nack& nack,
+ const shared_ptr<pit::Entry>& pitEntry) override;
+
+private: // operations
+
+ /** \brief Send an Interest to all possible faces
+ *
+ * This function is invoked when the forwarder has no matching FIB entries for
+ * an incoming discovery Interest, which will be forwarded to faces that
+ * - do not violate the Interest scope
+ * - are non-local
+ * - are not the face from which the Interest arrived, unless the face is ad-hoc
+ */
+ void
+ broadcastInterest(const Interest& interest, const Face& inFace,
+ const shared_ptr<pit::Entry>& pitEntry);
+
+ /** \brief Send an Interest to \p nexthops
+ */
+ void
+ multicastInterest(const Interest& interest, const Face& inFace,
+ const shared_ptr<pit::Entry>& pitEntry,
+ const fib::NextHopList& nexthops);
+
+ /** \brief Find a Prefix Announcement for the Data on the RIB thread, and forward
+ * the Data with the Prefix Announcement on the main thread
+ */
+ void
+ asyncProcessData(const shared_ptr<pit::Entry>& pitEntry, const Face& inFace, const Data& data);
+
+ /** \brief Check whether a PrefixAnnouncement needs to be attached to an incoming Data
+ *
+ * The conditions that a Data packet requires a PrefixAnnouncement are
+ * - the incoming Interest was discovery and
+ * - the outgoing Interest was non-discovery and
+ * - this forwarder does not directly connect to the consumer
+ */
+ static bool
+ needPrefixAnn(const shared_ptr<pit::Entry>& pitEntry);
+
+ /** \brief Add a route using RibManager::slAnnounce on the RIB thread
+ */
+ void
+ addRoute(const shared_ptr<pit::Entry>& pitEntry, const Face& inFace,
+ const Data& data, const ndn::PrefixAnnouncement& pa);
+
+ /** \brief renew a route using RibManager::slRenew on the RIB thread
+ */
+ void
+ renewRoute(const Name& name, FaceId inFaceId, time::milliseconds maxLifetime);
+
+private:
+ static const time::milliseconds ROUTE_RENEW_LIFETIME;
+};
+
+} // namespace fw
+} // namespace nfd
+
+#endif // NFD_DAEMON_FW_SELF_LEARNING_STRATEGY_HPP