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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
* Copyright (c) 2014, 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-load-balancer-strategy.hpp"
#include <boost/random/uniform_int_distribution.hpp>
#include <ndn-cxx/util/random.hpp>
#include "core/logger.hpp"
NFD_LOG_INIT("RandomLoadBalancerStrategy");
namespace nfd {
namespace fw {
const Name
RandomLoadBalancerStrategy::STRATEGY_NAME("ndn:/localhost/nfd/strategy/random-load-balancer");
RandomLoadBalancerStrategy::RandomLoadBalancerStrategy(Forwarder& forwarder, const Name& name)
: Strategy(forwarder, name)
{
}
RandomLoadBalancerStrategy::~RandomLoadBalancerStrategy()
{
}
static bool
canForwardToNextHop(const Face& inFace, shared_ptr<pit::Entry> pitEntry, const fib::NextHop& nexthop)
{
return !wouldViolateScope(inFace, pitEntry->getInterest(), nexthop.getFace()) &&
canForwardToLegacy(*pitEntry, nexthop.getFace());
}
static bool
hasFaceForForwarding(const Face& inFace, const fib::NextHopList& nexthops, const shared_ptr<pit::Entry>& pitEntry)
{
return std::find_if(nexthops.begin(), nexthops.end(), bind(&canForwardToNextHop, cref(inFace), pitEntry, _1))
!= nexthops.end();
}
void
RandomLoadBalancerStrategy::afterReceiveInterest(const Face& inFace, const Interest& interest,
const shared_ptr<pit::Entry>& pitEntry)
{
NFD_LOG_TRACE("afterReceiveInterest");
if (hasPendingOutRecords(*pitEntry)) {
// not a new Interest, don't forward
return;
}
const fib::Entry& fibEntry = this->lookupFib(*pitEntry);
const fib::NextHopList& nexthops = fibEntry.getNextHops();
// Ensure there is at least 1 Face is available for forwarding
if (!hasFaceForForwarding(inFace, nexthops, pitEntry)) {
this->rejectPendingInterest(pitEntry);
return;
}
fib::NextHopList::const_iterator selected;
do {
boost::random::uniform_int_distribution<> dist(0, nexthops.size() - 1);
const size_t randomIndex = dist(m_randomGenerator);
uint64_t currentIndex = 0;
for (selected = nexthops.begin(); selected != nexthops.end() && currentIndex != randomIndex;
++selected, ++currentIndex) {
}
} while (!canForwardToNextHop(inFace, pitEntry, *selected));
this->sendInterest(pitEntry, selected->getFace());
}
} // namespace fw
} // namespace nfd