src/route/name-prefix-table.cpp - NLSR - Gitiles

 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /**
  * Copyright (c) 2014-2019,  The University of Memphis,
  *                           Regents of the University of California,
  *                           Arizona Board of Regents.
  *
  * This file is part of NLSR (Named-data Link State Routing).
  * See AUTHORS.md for complete list of NLSR authors and contributors.
  *
  * NLSR 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.
  *
  * NLSR 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
  * NLSR, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
  **/

 #include "name-prefix-table.hpp"

 #include "logger.hpp"
 #include "nlsr.hpp"
 #include "routing-table.hpp"

 #include <algorithm>
 #include <list>
 #include <utility>

 namespace nlsr {

 INIT_LOGGER(route.NamePrefixTable);

 NamePrefixTable::NamePrefixTable(Fib& fib, RoutingTable& routingTable,
                                  std::unique_ptr<AfterRoutingChange>& afterRoutingChangeSignal)
   : m_fib(fib)
   , m_routingTable(routingTable)
 {
   m_afterRoutingChangeConnection = afterRoutingChangeSignal->connect(
     [this] (const std::list<RoutingTableEntry>& entries) {
       updateWithNewRoute(entries);
     });
 }

 NamePrefixTable::~NamePrefixTable()
 {
   m_afterRoutingChangeConnection.disconnect();
 }

 void
 NamePrefixTable::addEntry(const ndn::Name& name, const ndn::Name& destRouter)
 {

   // Check if the advertised name prefix is in the table already.
   NptEntryList::iterator nameItr =
     std::find_if(m_table.begin(),
                  m_table.end(),
                  [&] (const std::shared_ptr<NamePrefixTableEntry>& entry) {
                    return name == entry->getNamePrefix();
                  });

   // Attempt to find a routing table pool entry (RTPE) we can use.
   RoutingTableEntryPool::iterator rtpeItr = m_rtpool.find(destRouter);

   // These declarations just to make the compiler happy...
   RoutingTablePoolEntry rtpe;
   std::shared_ptr<RoutingTablePoolEntry> rtpePtr(nullptr);

   // There isn't currently a routing table entry in the pool for this name
   if (rtpeItr == m_rtpool.end()) {
     // See if there is a routing table entry available we could use
     RoutingTableEntry* routeEntryPtr = m_routingTable.findRoutingTableEntry(destRouter);

     // We have to create a new routing table entry
     if (routeEntryPtr == nullptr) {
       rtpe = RoutingTablePoolEntry(destRouter, 0);
     }
     // There was already a usable one in the routing table
     else {
       rtpe = RoutingTablePoolEntry(*routeEntryPtr, 0);
     }

     // Add the new pool object to the pool.
     rtpePtr = addRtpeToPool(rtpe);
   }
   // There was one already, so just fetch that one.
   else {
     rtpePtr = (*rtpeItr).second;
   }

   std::shared_ptr<NamePrefixTableEntry> npte;
   // Either we have to make a new NPT entry or there already was one.
   if (nameItr == m_table.end()) {
     NLSR_LOG_DEBUG("Adding origin: " << rtpePtr->getDestination()
                << " to a new name prefix: " << name);
     npte = make_shared<NamePrefixTableEntry>(name);
     npte->addRoutingTableEntry(rtpePtr);
     npte->generateNhlfromRteList();
     m_table.push_back(npte);
     // If this entry has next hops, we need to inform the FIB
     if (npte->getNexthopList().size() > 0) {
       NLSR_LOG_TRACE("Updating FIB with next hops for " << npte->getNamePrefix());
       m_fib.update(name, npte->getNexthopList());
     }
     // The routing table may recalculate and add a routing table entry
     // with no next hops to replace an existing routing table entry. In
     // this case, the name prefix is no longer reachable through a next
     // hop and should be removed from the FIB. But, the prefix should
     // remain in the Name Prefix Table as a future routing table
     // calculation may add next hops.
     else {
       NLSR_LOG_TRACE(npte->getNamePrefix() << " has no next hops; removing from FIB");
       m_fib.remove(name);
     }
   }
   else {
     npte = *nameItr;
     NLSR_LOG_TRACE("Adding origin: " << rtpePtr->getDestination() <<
                    " to existing prefix: " << **nameItr);
     (*nameItr)->addRoutingTableEntry(rtpePtr);
     (*nameItr)->generateNhlfromRteList();

     if ((*nameItr)->getNexthopList().size() > 0) {
       NLSR_LOG_TRACE("Updating FIB with next hops for " << (**nameItr));
       m_fib.update(name, (*nameItr)->getNexthopList());
     }
     else {
       NLSR_LOG_TRACE(npte->getNamePrefix() << " has no next hops; removing from FIB");
       m_fib.remove(name);
     }
   }
   // Add the reference to this NPT to the RTPE.
   rtpePtr->namePrefixTableEntries.emplace(
     std::make_pair(npte->getNamePrefix(), std::weak_ptr<NamePrefixTableEntry>(npte)));
 }

 void
 NamePrefixTable::removeEntry(const ndn::Name& name, const ndn::Name& destRouter)
 {
   NLSR_LOG_DEBUG("Removing origin: " << destRouter << " from " << name);

   // Fetch an iterator to the appropriate pair object in the pool.
   RoutingTableEntryPool::iterator rtpeItr = m_rtpool.find(destRouter);

   // Simple error checking to prevent any unusual behavior in the case
   // that we try to remove an entry that isn't there.
   if (rtpeItr == m_rtpool.end()) {
     NLSR_LOG_DEBUG("No entry for origin: " << destRouter
                << " found, so it cannot be removed from prefix: "
                << name);
     return;
   }
   std::shared_ptr<RoutingTablePoolEntry> rtpePtr = rtpeItr->second;

   // Ensure that the entry exists
   NptEntryList::iterator nameItr =
     std::find_if(m_table.begin(), m_table.end(),
                  [&] (const std::shared_ptr<NamePrefixTableEntry>& entry) {
                    return entry->getNamePrefix() == name;
                  });
   if (nameItr != m_table.end()) {
     NLSR_LOG_TRACE("Removing origin: " << rtpePtr->getDestination()
                << " from prefix: " << **nameItr);

     // Rather than iterating through the whole list periodically, just
     // delete them here if they have no references.
     if ((*nameItr)->removeRoutingTableEntry(rtpePtr) == 0) {
       deleteRtpeFromPool(rtpePtr);
     }

     // If the prefix is a router prefix and it does not have any other
     // routing table entries, the Adjacency/Coordinate LSA associated
     // with that origin router has been removed from the LSDB and so
     // the router prefix should be removed from the Name Prefix Table.
     //
     // If the prefix is an advertised name prefix: If another router
     //   advertises this name prefix, the RteList should have another
     //   entry for that router; the next hops should be recalculated
     //   and installed in the FIB.
     //
     //   If no other router advertises this name prefix, the RteList
     //   should be empty and the prefix can be removed from the Name
     //   Prefix Table. Once a new Name LSA advertises this prefix, a
     //   new entry for the prefix will be created.
     //
     if ((*nameItr)->getRteListSize() == 0) {
       NLSR_LOG_TRACE(**nameItr << " has no routing table entries;"
                  << " removing from table and FIB");
       m_table.erase(nameItr);
       m_fib.remove(name);
     }
     else {
       NLSR_LOG_TRACE(**nameItr << " has other routing table entries;"
                  << " updating FIB with next hops");
       (*nameItr)->generateNhlfromRteList();
       m_fib.update(name, (*nameItr)->getNexthopList());
     }
   }
   else {
     NLSR_LOG_DEBUG("Attempted to remove origin: " << rtpePtr->getDestination()
                << " from non-existent prefix: " << name);
   }
 }

 void
 NamePrefixTable::updateWithNewRoute(const std::list<RoutingTableEntry>& entries)
 {
   NLSR_LOG_DEBUG("Updating table with newly calculated routes");

   // Iterate over each pool entry we have
   for (auto&& poolEntryPair : m_rtpool) {
     auto&& poolEntry = poolEntryPair.second;
     auto sourceEntry = std::find_if(entries.begin(), entries.end(),
                                     [&poolEntry] (const RoutingTableEntry& entry) {
                                       return poolEntry->getDestination() == entry.getDestination();
                                     });
     // If this pool entry has a corresponding entry in the routing table now
     if (sourceEntry != entries.end()
         && poolEntry->getNexthopList() != sourceEntry->getNexthopList()) {
       NLSR_LOG_DEBUG("Routing entry: " << poolEntry->getDestination() << " has changed next-hops.");
       poolEntry->setNexthopList(sourceEntry->getNexthopList());
       for (const auto& nameEntry : poolEntry->namePrefixTableEntries) {
         auto nameEntryFullPtr = nameEntry.second.lock();
         addEntry(nameEntryFullPtr->getNamePrefix(), poolEntry->getDestination());
       }
     }
     else if (sourceEntry == entries.end()) {
       NLSR_LOG_DEBUG("Routing entry: " << poolEntry->getDestination() << " now has no next-hops.");
       poolEntry->getNexthopList().reset();
       for (const auto& nameEntry : poolEntry->namePrefixTableEntries) {
         auto nameEntryFullPtr = nameEntry.second.lock();
         addEntry(nameEntryFullPtr->getNamePrefix(), poolEntry->getDestination());
       }
     }
     else {
       NLSR_LOG_TRACE("No change in routing entry:" << poolEntry->getDestination()
                  << ", no action necessary.");
     }
   }
 }

   // Inserts the routing table pool entry into the NPT's RTE storage
   // pool.  This cannot fail, so the pool is guaranteed to contain the
   // item after this occurs.
 std::shared_ptr<RoutingTablePoolEntry>
 NamePrefixTable::addRtpeToPool(RoutingTablePoolEntry& rtpe)
 {
   RoutingTableEntryPool::iterator poolItr =
     m_rtpool.insert(std::make_pair(rtpe.getDestination(),
                                    std::make_shared<RoutingTablePoolEntry>
                                    (rtpe)))
     .first;
   return poolItr->second;
 }

   // Removes the routing table pool entry from the storage pool. The
   // postconditions of this function are guaranteed to include that
   // the storage pool does not contain such an item. Additionally,
   // this function cannot fail, but nonetheless debug information is
   // given in the case that this function is called with an entry that
   // isn't in the pool.
 void
 NamePrefixTable::deleteRtpeFromPool(std::shared_ptr<RoutingTablePoolEntry> rtpePtr)
 {
   if (m_rtpool.erase(rtpePtr->getDestination()) != 1) {
     NLSR_LOG_DEBUG("Attempted to delete non-existent origin: "
                << rtpePtr->getDestination()
                << " from NPT routing table entry storage pool.");
   }
 }

 void
 NamePrefixTable::writeLog()
 {
   NLSR_LOG_DEBUG(*this);
 }

 std::ostream&
 operator<<(std::ostream& os, const NamePrefixTable& table)
 {
   os << "----------------NPT----------------------\n";

   for (const auto& entryPtr : table) {
     os << *entryPtr << std::endl;
   }

   return os;
 }

 } // namespace nlsr
	/* -- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -- */
	/**
	* Copyright (c) 2014-2019, The University of Memphis,
	* Regents of the University of California,
	* Arizona Board of Regents.
	*
	* This file is part of NLSR (Named-data Link State Routing).
	* See AUTHORS.md for complete list of NLSR authors and contributors.
	*
	* NLSR 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.
	*
	* NLSR 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
	* NLSR, e.g., in COPYING.md file. If not, see <http://www.gnu.org/licenses/>.
	**/

	#include "name-prefix-table.hpp"

	#include "logger.hpp"
	#include "nlsr.hpp"
	#include "routing-table.hpp"

	#include <algorithm>
	#include <list>
	#include <utility>

	namespace nlsr {

	INIT_LOGGER(route.NamePrefixTable);

	NamePrefixTable::NamePrefixTable(Fib& fib, RoutingTable& routingTable,
	std::unique_ptr<AfterRoutingChange>& afterRoutingChangeSignal)
	: m_fib(fib)
	, m_routingTable(routingTable)
	{
	m_afterRoutingChangeConnection = afterRoutingChangeSignal->connect(
	[this] (const std::list<RoutingTableEntry>& entries) {
	updateWithNewRoute(entries);
	});
	}

	NamePrefixTable::~NamePrefixTable()
	{
	m_afterRoutingChangeConnection.disconnect();
	}

	void
	NamePrefixTable::addEntry(const ndn::Name& name, const ndn::Name& destRouter)
	{

	// Check if the advertised name prefix is in the table already.
	NptEntryList::iterator nameItr =
	std::find_if(m_table.begin(),
	m_table.end(),
	[&] (const std::shared_ptr<NamePrefixTableEntry>& entry) {
	return name == entry->getNamePrefix();
	});

	// Attempt to find a routing table pool entry (RTPE) we can use.
	RoutingTableEntryPool::iterator rtpeItr = m_rtpool.find(destRouter);

	// These declarations just to make the compiler happy...
	RoutingTablePoolEntry rtpe;
	std::shared_ptr<RoutingTablePoolEntry> rtpePtr(nullptr);

	// There isn't currently a routing table entry in the pool for this name
	if (rtpeItr == m_rtpool.end()) {
	// See if there is a routing table entry available we could use
	RoutingTableEntry* routeEntryPtr = m_routingTable.findRoutingTableEntry(destRouter);

	// We have to create a new routing table entry
	if (routeEntryPtr == nullptr) {
	rtpe = RoutingTablePoolEntry(destRouter, 0);
	}
	// There was already a usable one in the routing table
	else {
	rtpe = RoutingTablePoolEntry(*routeEntryPtr, 0);
	}

	// Add the new pool object to the pool.
	rtpePtr = addRtpeToPool(rtpe);
	}
	// There was one already, so just fetch that one.
	else {
	rtpePtr = (*rtpeItr).second;
	}

	std::shared_ptr<NamePrefixTableEntry> npte;
	// Either we have to make a new NPT entry or there already was one.
	if (nameItr == m_table.end()) {
	NLSR_LOG_DEBUG("Adding origin: " << rtpePtr->getDestination()
	<< " to a new name prefix: " << name);
	npte = make_shared<NamePrefixTableEntry>(name);
	npte->addRoutingTableEntry(rtpePtr);
	npte->generateNhlfromRteList();
	m_table.push_back(npte);
	// If this entry has next hops, we need to inform the FIB
	if (npte->getNexthopList().size() > 0) {
	NLSR_LOG_TRACE("Updating FIB with next hops for " << npte->getNamePrefix());
	m_fib.update(name, npte->getNexthopList());
	}
	// The routing table may recalculate and add a routing table entry
	// with no next hops to replace an existing routing table entry. In
	// this case, the name prefix is no longer reachable through a next
	// hop and should be removed from the FIB. But, the prefix should
	// remain in the Name Prefix Table as a future routing table
	// calculation may add next hops.
	else {
	NLSR_LOG_TRACE(npte->getNamePrefix() << " has no next hops; removing from FIB");
	m_fib.remove(name);
	}
	}
	else {
	npte = *nameItr;
	NLSR_LOG_TRACE("Adding origin: " << rtpePtr->getDestination() <<
	" to existing prefix: " << **nameItr);
	(*nameItr)->addRoutingTableEntry(rtpePtr);
	(*nameItr)->generateNhlfromRteList();

	if ((*nameItr)->getNexthopList().size() > 0) {
	NLSR_LOG_TRACE("Updating FIB with next hops for " << (**nameItr));
	m_fib.update(name, (*nameItr)->getNexthopList());
	}
	else {
	NLSR_LOG_TRACE(npte->getNamePrefix() << " has no next hops; removing from FIB");
	m_fib.remove(name);
	}
	}
	// Add the reference to this NPT to the RTPE.
	rtpePtr->namePrefixTableEntries.emplace(
	std::make_pair(npte->getNamePrefix(), std::weak_ptr<NamePrefixTableEntry>(npte)));
	}

	void
	NamePrefixTable::removeEntry(const ndn::Name& name, const ndn::Name& destRouter)
	{
	NLSR_LOG_DEBUG("Removing origin: " << destRouter << " from " << name);

	// Fetch an iterator to the appropriate pair object in the pool.
	RoutingTableEntryPool::iterator rtpeItr = m_rtpool.find(destRouter);

	// Simple error checking to prevent any unusual behavior in the case
	// that we try to remove an entry that isn't there.
	if (rtpeItr == m_rtpool.end()) {
	NLSR_LOG_DEBUG("No entry for origin: " << destRouter
	<< " found, so it cannot be removed from prefix: "
	<< name);
	return;
	}
	std::shared_ptr<RoutingTablePoolEntry> rtpePtr = rtpeItr->second;

	// Ensure that the entry exists
	NptEntryList::iterator nameItr =
	std::find_if(m_table.begin(), m_table.end(),
	[&] (const std::shared_ptr<NamePrefixTableEntry>& entry) {
	return entry->getNamePrefix() == name;
	});
	if (nameItr != m_table.end()) {
	NLSR_LOG_TRACE("Removing origin: " << rtpePtr->getDestination()
	<< " from prefix: " << **nameItr);

	// Rather than iterating through the whole list periodically, just
	// delete them here if they have no references.
	if ((*nameItr)->removeRoutingTableEntry(rtpePtr) == 0) {
	deleteRtpeFromPool(rtpePtr);
	}

	// If the prefix is a router prefix and it does not have any other
	// routing table entries, the Adjacency/Coordinate LSA associated
	// with that origin router has been removed from the LSDB and so
	// the router prefix should be removed from the Name Prefix Table.
	//
	// If the prefix is an advertised name prefix: If another router
	// advertises this name prefix, the RteList should have another
	// entry for that router; the next hops should be recalculated
	// and installed in the FIB.
	//
	// If no other router advertises this name prefix, the RteList
	// should be empty and the prefix can be removed from the Name
	// Prefix Table. Once a new Name LSA advertises this prefix, a
	// new entry for the prefix will be created.
	//
	if ((*nameItr)->getRteListSize() == 0) {
	NLSR_LOG_TRACE(**nameItr << " has no routing table entries;"
	<< " removing from table and FIB");
	m_table.erase(nameItr);
	m_fib.remove(name);
	}
	else {
	NLSR_LOG_TRACE(**nameItr << " has other routing table entries;"
	<< " updating FIB with next hops");
	(*nameItr)->generateNhlfromRteList();
	m_fib.update(name, (*nameItr)->getNexthopList());
	}
	}
	else {
	NLSR_LOG_DEBUG("Attempted to remove origin: " << rtpePtr->getDestination()
	<< " from non-existent prefix: " << name);
	}
	}

	void
	NamePrefixTable::updateWithNewRoute(const std::list<RoutingTableEntry>& entries)
	{
	NLSR_LOG_DEBUG("Updating table with newly calculated routes");

	// Iterate over each pool entry we have
	for (auto&& poolEntryPair : m_rtpool) {
	auto&& poolEntry = poolEntryPair.second;
	auto sourceEntry = std::find_if(entries.begin(), entries.end(),
	[&poolEntry] (const RoutingTableEntry& entry) {
	return poolEntry->getDestination() == entry.getDestination();
	});
	// If this pool entry has a corresponding entry in the routing table now
	if (sourceEntry != entries.end()
	&& poolEntry->getNexthopList() != sourceEntry->getNexthopList()) {
	NLSR_LOG_DEBUG("Routing entry: " << poolEntry->getDestination() << " has changed next-hops.");
	poolEntry->setNexthopList(sourceEntry->getNexthopList());
	for (const auto& nameEntry : poolEntry->namePrefixTableEntries) {
	auto nameEntryFullPtr = nameEntry.second.lock();
	addEntry(nameEntryFullPtr->getNamePrefix(), poolEntry->getDestination());
	}
	}
	else if (sourceEntry == entries.end()) {
	NLSR_LOG_DEBUG("Routing entry: " << poolEntry->getDestination() << " now has no next-hops.");
	poolEntry->getNexthopList().reset();
	for (const auto& nameEntry : poolEntry->namePrefixTableEntries) {
	auto nameEntryFullPtr = nameEntry.second.lock();
	addEntry(nameEntryFullPtr->getNamePrefix(), poolEntry->getDestination());
	}
	}
	else {
	NLSR_LOG_TRACE("No change in routing entry:" << poolEntry->getDestination()
	<< ", no action necessary.");
	}
	}
	}

	// Inserts the routing table pool entry into the NPT's RTE storage
	// pool. This cannot fail, so the pool is guaranteed to contain the
	// item after this occurs.
	std::shared_ptr<RoutingTablePoolEntry>
	NamePrefixTable::addRtpeToPool(RoutingTablePoolEntry& rtpe)
	{
	RoutingTableEntryPool::iterator poolItr =
	m_rtpool.insert(std::make_pair(rtpe.getDestination(),
	std::make_shared<RoutingTablePoolEntry>
	(rtpe)))
	.first;
	return poolItr->second;
	}

	// Removes the routing table pool entry from the storage pool. The
	// postconditions of this function are guaranteed to include that
	// the storage pool does not contain such an item. Additionally,
	// this function cannot fail, but nonetheless debug information is
	// given in the case that this function is called with an entry that
	// isn't in the pool.
	void
	NamePrefixTable::deleteRtpeFromPool(std::shared_ptr<RoutingTablePoolEntry> rtpePtr)
	{
	if (m_rtpool.erase(rtpePtr->getDestination()) != 1) {
	NLSR_LOG_DEBUG("Attempted to delete non-existent origin: "
	<< rtpePtr->getDestination()
	<< " from NPT routing table entry storage pool.");
	}
	}

	void
	NamePrefixTable::writeLog()
	{
	NLSR_LOG_DEBUG(*this);
	}

	std::ostream&
	operator<<(std::ostream& os, const NamePrefixTable& table)
	{
	os << "----------------NPT----------------------\n";

	for (const auto& entryPtr : table) {
	os << *entryPtr << std::endl;
	}

	return os;
	}

	} // namespace nlsr