rib: introduce Readvertise

refs #3818

Change-Id: I4635fecfcb8be5d9bb3086dea3bf7bbd90538832
diff --git a/rib/readvertise/readvertise.cpp b/rib/readvertise/readvertise.cpp
new file mode 100644
index 0000000..c585bf5
--- /dev/null
+++ b/rib/readvertise/readvertise.cpp
@@ -0,0 +1,198 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2017,  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 "readvertise.hpp"
+#include "core/logger.hpp"
+#include "core/random.hpp"
+
+namespace nfd {
+namespace rib {
+
+NFD_LOG_INIT("Readvertise");
+
+const time::milliseconds Readvertise::RETRY_DELAY_MIN = time::seconds(50);
+const time::milliseconds Readvertise::RETRY_DELAY_MAX = time::seconds(3600);
+
+static time::milliseconds
+randomizeTimer(time::milliseconds baseTimer)
+{
+  std::uniform_int_distribution<uint64_t> dist(-5, 5);
+  time::milliseconds newTime = baseTimer + time::milliseconds(dist(getGlobalRng()));
+  return std::max(newTime, time::milliseconds(0));
+}
+
+Readvertise::Readvertise(Rib& rib, unique_ptr<ReadvertisePolicy> policy,
+                         unique_ptr<ReadvertiseDestination> destination)
+  : m_policy(std::move(policy))
+  , m_destination(std::move(destination))
+{
+  m_addRouteConn = rib.afterAddRoute.connect(bind(&Readvertise::afterAddRoute, this, _1));
+  m_removeRouteConn = rib.beforeRemoveRoute.connect(bind(&Readvertise::beforeRemoveRoute, this, _1));
+
+  m_destination->afterAvailabilityChange.connect([this] (bool isAvailable) {
+    if (isAvailable) {
+      this->afterDestinationAvailable();
+    }
+    else {
+      this->afterDestinationUnavailable();
+    }
+  });
+}
+
+void
+Readvertise::afterAddRoute(const RibRouteRef& ribRoute)
+{
+  ndn::optional<ReadvertiseAction> action = m_policy->handleNewRoute(ribRoute);
+  if (!action) {
+    NFD_LOG_DEBUG("add-route " << ribRoute.entry->getName() << '(' << ribRoute.route->faceId <<
+                  ',' << ribRoute.route->origin << ") not-readvertising");
+    return;
+  }
+
+  ReadvertisedRouteContainer::iterator rrIt;
+  bool isNew = false;
+  std::tie(rrIt, isNew) = m_rrs.emplace(action->prefix);
+
+  if (!isNew && rrIt->signer != action->signer) {
+    NFD_LOG_WARN("add-route " << ribRoute.entry->getName() << '(' << ribRoute.route->faceId <<
+                  ',' << ribRoute.route->origin << ") readvertising-as " << action->prefix <<
+                 " old-signer " << rrIt->signer << " new-signer " << action->signer);
+  }
+  rrIt->signer = action->signer;
+
+  RouteRrIndex::iterator indexIt;
+  std::tie(indexIt, isNew) = m_routeToRr.emplace(ribRoute, rrIt);
+  BOOST_ASSERT(isNew);
+
+  if (rrIt->nRibRoutes++ > 0) {
+    NFD_LOG_DEBUG("add-route " << ribRoute.entry->getName() << '(' << ribRoute.route->faceId <<
+                  ',' << ribRoute.route->origin << ") already-readvertised-as " << action->prefix);
+    return;
+  }
+
+  NFD_LOG_DEBUG("add-route " << ribRoute.entry->getName() << '(' << ribRoute.route->faceId <<
+                ',' << ribRoute.route->origin << ") readvertising-as " << action->prefix <<
+                " signer " << action->signer);
+  rrIt->retryDelay = RETRY_DELAY_MIN;
+  this->advertise(rrIt);
+}
+
+void
+Readvertise::beforeRemoveRoute(const RibRouteRef& ribRoute)
+{
+  auto indexIt = m_routeToRr.find(ribRoute);
+  if (indexIt == m_routeToRr.end()) {
+    NFD_LOG_DEBUG("remove-route " << ribRoute.entry->getName() << '(' << ribRoute.route->faceId <<
+                  ',' << ribRoute.route->origin << ") not-readvertised");
+    return;
+  }
+
+  auto rrIt = indexIt->second;
+  m_routeToRr.erase(indexIt);
+
+  if (--rrIt->nRibRoutes > 0) {
+    NFD_LOG_DEBUG("remove-route " << ribRoute.entry->getName() << '(' << ribRoute.route->faceId <<
+                  ',' << ribRoute.route->origin << ") needed-by " << rrIt->nRibRoutes);
+    return;
+  }
+
+  rrIt->retryDelay = RETRY_DELAY_MIN;
+  this->withdraw(rrIt);
+}
+
+void
+Readvertise::afterDestinationAvailable()
+{
+  for (auto rrIt = m_rrs.begin(); rrIt != m_rrs.end(); ++rrIt) {
+    rrIt->retryDelay = RETRY_DELAY_MIN;
+    this->advertise(rrIt);
+  }
+}
+
+void
+Readvertise::afterDestinationUnavailable()
+{
+  for (auto rrIt = m_rrs.begin(); rrIt != m_rrs.end();) {
+    if (rrIt->nRibRoutes > 0) {
+      rrIt->retryEvt.cancel(); // stop retrying or refreshing
+      ++rrIt;
+    }
+    else {
+      rrIt = m_rrs.erase(rrIt); // assume withdraw has completed
+    }
+  }
+}
+
+void
+Readvertise::advertise(ReadvertisedRouteContainer::iterator rrIt)
+{
+  BOOST_ASSERT(rrIt->nRibRoutes > 0);
+
+  if (!m_destination->isAvailable()) {
+    NFD_LOG_DEBUG("advertise " << rrIt->prefix << " destination-unavailable");
+    return;
+  }
+
+  m_destination->advertise(*rrIt,
+    [this, rrIt] {
+      NFD_LOG_DEBUG("advertise " << rrIt->prefix << " success");
+      rrIt->retryDelay = RETRY_DELAY_MIN;
+      rrIt->retryEvt = scheduler::schedule(randomizeTimer(m_policy->getRefreshInterval()),
+                                           bind(&Readvertise::advertise, this, rrIt));
+    },
+    [this, rrIt] (const std::string& msg) {
+      NFD_LOG_DEBUG("advertise " << rrIt->prefix << " failure " << msg);
+      rrIt->retryDelay = std::min(RETRY_DELAY_MAX, rrIt->retryDelay * 2);
+      rrIt->retryEvt = scheduler::schedule(randomizeTimer(rrIt->retryDelay),
+                                           bind(&Readvertise::advertise, this, rrIt));
+    });
+}
+
+void
+Readvertise::withdraw(ReadvertisedRouteContainer::iterator rrIt)
+{
+  BOOST_ASSERT(rrIt->nRibRoutes == 0);
+
+  if (!m_destination->isAvailable()) {
+    NFD_LOG_DEBUG("withdraw " << rrIt->prefix << " destination-unavailable");
+    m_rrs.erase(rrIt);
+    return;
+  }
+
+  m_destination->withdraw(*rrIt,
+    [this, rrIt] {
+      NFD_LOG_DEBUG("withdraw " << rrIt->prefix << " success");
+      m_rrs.erase(rrIt);
+    },
+    [this, rrIt] (const std::string& msg) {
+      NFD_LOG_DEBUG("withdraw " << rrIt->prefix << " failure " << msg);
+      rrIt->retryDelay = std::min(RETRY_DELAY_MAX, rrIt->retryDelay * 2);
+      rrIt->retryEvt = scheduler::schedule(randomizeTimer(rrIt->retryDelay),
+                                           bind(&Readvertise::withdraw, this, rrIt));
+    });
+}
+
+} // namespace rib
+} // namespace nfd
diff --git a/rib/readvertise/readvertise.hpp b/rib/readvertise/readvertise.hpp
new file mode 100644
index 0000000..13a6e59
--- /dev/null
+++ b/rib/readvertise/readvertise.hpp
@@ -0,0 +1,93 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2014-2017,  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_RIB_READVERTISE_READVERTISE_HPP
+#define NFD_RIB_READVERTISE_READVERTISE_HPP
+
+#include "readvertise-destination.hpp"
+#include "readvertise-policy.hpp"
+#include "readvertised-route.hpp"
+#include "../rib.hpp"
+#include "core/scheduler.hpp"
+
+namespace nfd {
+namespace rib {
+
+/** \brief readvertise a subset of routes to a destination according to a policy
+ *
+ *  The Readvertise class allows RIB routes to be readvertised to a destination such as a routing
+ *  protocol daemon or another NFD-RIB. It monitors the RIB for route additions and removals,
+ *  asks the ReadvertisePolicy to make decision on whether to readvertise each new route and what
+ *  prefix to readvertise as, and invokes a ReadvertiseDestination to send the commands.
+ */
+class Readvertise : noncopyable
+{
+
+public:
+  Readvertise(Rib& rib,
+              unique_ptr<ReadvertisePolicy> policy,
+              unique_ptr<ReadvertiseDestination> destination);
+
+private:
+  void
+  afterAddRoute(const RibRouteRef& ribRoute);
+
+  void
+  beforeRemoveRoute(const RibRouteRef& ribRoute);
+
+  void
+  afterDestinationAvailable();
+
+  void
+  afterDestinationUnavailable();
+
+  void
+  advertise(ReadvertisedRouteContainer::iterator rrIt);
+
+  void
+  withdraw(ReadvertisedRouteContainer::iterator rrIt);
+
+private:
+  /** \brief maps from RIB route to readvertised route derived from RIB route(s)
+   */
+  using RouteRrIndex = std::map<RibRouteRef, ReadvertisedRouteContainer::iterator>;
+
+  static const time::milliseconds RETRY_DELAY_MIN;
+  static const time::milliseconds RETRY_DELAY_MAX;
+
+  unique_ptr<ReadvertisePolicy> m_policy;
+  unique_ptr<ReadvertiseDestination> m_destination;
+
+  ReadvertisedRouteContainer m_rrs;
+  RouteRrIndex m_routeToRr;
+
+  signal::ScopedConnection m_addRouteConn;
+  signal::ScopedConnection m_removeRouteConn;
+};
+
+} // namespace rib
+} // namespace nfd
+
+#endif // NFD_RIB_READVERTISE_READVERTISE_HPP