dsr-rcache.cc

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/*
 * Copyright (c) 2011 Yufei Cheng
 *
 * SPDX-License-Identifier: GPL-2.0-only
 *
 * Author: Yufei Cheng   <yfcheng@ittc.ku.edu>
 *              Song Luan <lsuper@mail.ustc.edu.cn> (Implemented Link Cache using Dijsktra
 * algorithm)
 *
 * James P.G. Sterbenz <jpgs@ittc.ku.edu>, director
 * ResiliNets Research Group  https://resilinets.org/
 * Information and Telecommunication Technology Center (ITTC)
 * and Department of Electrical Engineering and Computer Science
 * The University of Kansas Lawrence, KS USA.
 *
 * Work supported in part by NSF FIND (Future Internet Design) Program
 * under grant CNS-0626918 (Postmodern Internet Architecture),
 * NSF grant CNS-1050226 (Multilayer Network Resilience Analysis and Experimentation on GENI),
 * US Department of Defense (DoD), and ITTC at The University of Kansas.
 */
 
#include "dsr-rcache.h"
 
#include "ns3/address-utils.h"
#include "ns3/ipv4-route.h"
#include "ns3/log.h"
#include "ns3/packet.h"
#include "ns3/simulator.h"
#include "ns3/socket.h"
#include "ns3/wifi-mac-header.h"
 
#include <algorithm>
#include <cmath>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <vector>
 
namespace ns3
{
 
NS_LOG_COMPONENT_DEFINE("DsrRouteCache");
 
namespace dsr
{
 
bool
CompareRoutesBoth(const DsrRouteCacheEntry& a, const DsrRouteCacheEntry& b)
{
    // compare based on both with hop count considered priority
    return (a.GetVector().size() < b.GetVector().size()) ||
           ((a.GetVector().size() == b.GetVector().size()) &&
            (a.GetExpireTime() > b.GetExpireTime()));
}
 
bool
CompareRoutesHops(const DsrRouteCacheEntry& a, const DsrRouteCacheEntry& b)
{
    // compare based on hops
    return a.GetVector().size() < b.GetVector().size();
}
 
bool
CompareRoutesExpire(const DsrRouteCacheEntry& a, const DsrRouteCacheEntry& b)
{
    // compare based on expire time
    return a.GetExpireTime() > b.GetExpireTime();
}
 
void
Link::Print() const
{
    NS_LOG_DEBUG(m_low << "----" << m_high);
}
 
DsrNodeStab::DsrNodeStab(Time nodeStab)
    : m_nodeStability(nodeStab + Simulator::Now())
{
}
 
DsrNodeStab::~DsrNodeStab()
{
}
 
DsrLinkStab::DsrLinkStab(Time linkStab)
    : m_linkStability(linkStab + Simulator::Now())
{
}
 
DsrLinkStab::~DsrLinkStab()
{
}
 
void
DsrLinkStab::Print() const
{
    NS_LOG_LOGIC("LifeTime: " << GetLinkStability().As(Time::S));
}
 
typedef std::list<DsrRouteCacheEntry>::value_type route_pair;
 
DsrRouteCacheEntry::DsrRouteCacheEntry(IP_VECTOR const& ip, Ipv4Address dst, Time exp)
    : m_ackTimer(Timer::CANCEL_ON_DESTROY),
      m_dst(dst),
      m_path(ip),
      m_expire(exp + Simulator::Now()),
      m_reqCount(0),
      m_blackListState(false),
      m_blackListTimeout(Simulator::Now())
{
}
 
DsrRouteCacheEntry::~DsrRouteCacheEntry()
{
}
 
void
DsrRouteCacheEntry::Invalidate(Time badLinkLifetime)
{
    m_reqCount = 0;
    m_expire = badLinkLifetime + Simulator::Now();
}
 
void
DsrRouteCacheEntry::Print(std::ostream& os) const
{
    os << m_dst << "\t" << (m_expire - Simulator::Now()).As(Time::S) << "\t";
}
 
NS_OBJECT_ENSURE_REGISTERED(DsrRouteCache);
 
TypeId
DsrRouteCache::GetTypeId()
{
    static TypeId tid = TypeId("ns3::dsr::DsrRouteCache")
                            .SetParent<Object>()
                            .SetGroupName("Dsr")
                            .AddConstructor<DsrRouteCache>();
    return tid;
}
 
DsrRouteCache::DsrRouteCache()
    : m_vector(0),
      m_maxEntriesEachDst(3),
      m_isLinkCache(false),
      m_ntimer(Timer::CANCEL_ON_DESTROY),
      m_delay(MilliSeconds(100))
{
    /*
     * The timer to set layer 2 notification, not fully supported by ns3 yet
     */
    m_ntimer.SetDelay(m_delay);
    m_ntimer.SetFunction(&DsrRouteCache::PurgeMac, this);
}
 
DsrRouteCache::~DsrRouteCache()
{
    NS_LOG_FUNCTION_NOARGS();
    // clear the route cache when done
    m_sortedRoutes.clear();
}
 
void
DsrRouteCache::RemoveLastEntry(std::list<DsrRouteCacheEntry>& rtVector)
{
    NS_LOG_FUNCTION(this);
    // Release the last entry of route list
    rtVector.pop_back();
}
 
bool
DsrRouteCache::UpdateRouteEntry(Ipv4Address dst)
{
    NS_LOG_FUNCTION(this << dst);
    auto i = m_sortedRoutes.find(dst);
    if (i == m_sortedRoutes.end())
    {
        NS_LOG_LOGIC("Failed to find the route entry for the destination " << dst);
        return false;
    }
    else
    {
        std::list<DsrRouteCacheEntry> rtVector = i->second;
        DsrRouteCacheEntry successEntry = rtVector.front();
        successEntry.SetExpireTime(RouteCacheTimeout);
        rtVector.pop_front();
        rtVector.push_back(successEntry);
        rtVector.sort(CompareRoutesExpire); // sort the route vector first
        m_sortedRoutes.erase(dst);          // erase the entry first
        /*
         * Save the new route cache along with the destination address in map
         */
        auto result = m_sortedRoutes.insert(std::make_pair(dst, rtVector));
        return result.second;
    }
    return false;
}
 
bool
DsrRouteCache::LookupRoute(Ipv4Address id, DsrRouteCacheEntry& rt)
{
    NS_LOG_FUNCTION(this << id);
    if (IsLinkCache())
    {
        return LookupRoute_Link(id, rt);
    }
 
    Purge(); // Purge first to remove expired entries
    if (m_sortedRoutes.empty())
    {
        NS_LOG_LOGIC("Route to " << id << " not found; m_sortedRoutes is empty");
        return false;
    }
    auto i = m_sortedRoutes.find(id);
    if (i == m_sortedRoutes.end())
    {
        NS_LOG_LOGIC("No Direct Route to " << id << " found");
        for (auto j = m_sortedRoutes.begin(); j != m_sortedRoutes.end(); ++j)
        {
            std::list<DsrRouteCacheEntry> rtVector =
                j->second; // The route cache vector linked with destination address
            /*
             * Loop through the possibly multiple routes within the route vector
             */
            for (auto k = rtVector.begin(); k != rtVector.end(); ++k)
            {
                // return the first route in the route vector
                DsrRouteCacheEntry::IP_VECTOR routeVector = k->GetVector();
                DsrRouteCacheEntry::IP_VECTOR changeVector;
 
                for (auto l = routeVector.begin(); l != routeVector.end(); ++l)
                {
                    changeVector.push_back(*l);
 
                    if (*l == id)
                    {
                        break;
                    }
                }
                /*
                 * When the changed vector is smaller in size and larger than 1, which means we
                 * have found a route with the destination address we are looking for
                 */
                if ((changeVector.size() < routeVector.size()) && (changeVector.size() > 1))
                {
                    DsrRouteCacheEntry changeEntry; // Create the route entry
                    changeEntry.SetVector(changeVector);
                    changeEntry.SetDestination(id);
                    // Use the expire time from original route entry
                    changeEntry.SetExpireTime(k->GetExpireTime());
                    // We need to add new route entry here
                    std::list<DsrRouteCacheEntry> newVector;
                    newVector.push_back(changeEntry);
                    newVector.sort(CompareRoutesExpire); // sort the route vector first
                    m_sortedRoutes[id] =
                        newVector; // Only get the first sub route and add it in route cache
                    NS_LOG_INFO("We have a sub-route to " << id << " add it in route cache");
                }
            }
        }
    }
    NS_LOG_INFO("Here we check the route cache again after updated the sub routes");
    auto m = m_sortedRoutes.find(id);
    if (m == m_sortedRoutes.end())
    {
        NS_LOG_LOGIC("No updated route till last time");
        return false;
    }
    /*
     * We have a direct route to the destination address
     */
    std::list<DsrRouteCacheEntry> rtVector = m->second;
    rt = rtVector.front(); // use the first entry in the route vector
    NS_LOG_LOGIC("Route to " << id << " with route size " << rtVector.size());
    return true;
}
 
void
DsrRouteCache::SetCacheType(std::string type)
{
    NS_LOG_FUNCTION(this << type);
    if (type == "LinkCache")
    {
        m_isLinkCache = true;
    }
    else if (type == "PathCache")
    {
        m_isLinkCache = false;
    }
    else
    {
        m_isLinkCache = true; // use link cache as default
        NS_LOG_INFO("Error Cache Type");
    }
}
 
bool
DsrRouteCache::IsLinkCache()
{
    NS_LOG_FUNCTION(this);
    return m_isLinkCache;
}
 
void
DsrRouteCache::RebuildBestRouteTable(Ipv4Address source)
{
    NS_LOG_FUNCTION(this << source);
    /**
     * \brief The following are initialize-single-source
     */
    // @d shortest-path estimate
    std::map<Ipv4Address, uint32_t> d;
    // @pre preceding node
    std::map<Ipv4Address, Ipv4Address> pre;
    for (auto i = m_netGraph.begin(); i != m_netGraph.end(); ++i)
    {
        if (i->second.find(source) != i->second.end())
        {
            d[i->first] = i->second[source];
            pre[i->first] = source;
        }
        else
        {
            d[i->first] = MAXWEIGHT;
            pre[i->first] = Ipv4Address("255.255.255.255");
        }
    }
    d[source] = 0;
    /**
     * \brief The following is the core of Dijkstra algorithm
     */
    // the node set which shortest distance has been calculated, if true calculated
    std::map<Ipv4Address, bool> s;
    double temp = MAXWEIGHT;
    Ipv4Address tempip("255.255.255.255");
    for (uint32_t i = 0; i < m_netGraph.size(); i++)
    {
        temp = MAXWEIGHT;
        for (auto j = d.begin(); j != d.end(); ++j)
        {
            Ipv4Address ip = j->first;
            if (s.find(ip) == s.end())
            {
                /*
                 * \brief The following are for comparison
                 */
                if (j->second <= temp)
                {
                    temp = j->second;
                    tempip = ip;
                }
            }
        }
        if (!tempip.IsBroadcast())
        {
            s[tempip] = true;
            for (auto k = m_netGraph[tempip].begin(); k != m_netGraph[tempip].end(); ++k)
            {
                if (s.find(k->first) == s.end() && d[k->first] > d[tempip] + k->second)
                {
                    d[k->first] = d[tempip] + k->second;
                    pre[k->first] = tempip;
                }
                /*
                 *  Selects the shortest-length route that has the longest expected lifetime
                 *  (highest minimum timeout of any link in the route)
                 *  For the computation overhead and complexity
                 *  Here I just implement kind of greedy strategy to select link with the longest
                 * expected lifetime when there is two options
                 */
                else if (d[k->first] == d[tempip] + k->second)
                {
                    auto oldlink = m_linkCache.find(Link(k->first, pre[k->first]));
                    auto newlink = m_linkCache.find(Link(k->first, tempip));
                    if (oldlink != m_linkCache.end() && newlink != m_linkCache.end())
                    {
                        if (oldlink->second.GetLinkStability() < newlink->second.GetLinkStability())
                        {
                            NS_LOG_INFO("Select the link with longest expected lifetime");
                            d[k->first] = d[tempip] + k->second;
                            pre[k->first] = tempip;
                        }
                    }
                    else
                    {
                        NS_LOG_INFO("Link Stability Info Corrupt");
                    }
                }
            }
        }
    }
    // clean the best route table
    m_bestRoutesTable_link.clear();
    for (auto i = pre.begin(); i != pre.end(); ++i)
    {
        // loop for all vertices
        DsrRouteCacheEntry::IP_VECTOR route;
        Ipv4Address iptemp = i->first;
 
        if (!i->second.IsBroadcast() && iptemp != source)
        {
            while (iptemp != source)
            {
                route.push_back(iptemp);
                iptemp = pre[iptemp];
            }
            route.push_back(source);
            // Reverse the route
            DsrRouteCacheEntry::IP_VECTOR reverseroute(route.rbegin(), route.rend());
            NS_LOG_LOGIC("Add newly calculated best routes");
            PrintVector(reverseroute);
            m_bestRoutesTable_link[i->first] = reverseroute;
        }
    }
}
 
bool
DsrRouteCache::LookupRoute_Link(Ipv4Address id, DsrRouteCacheEntry& rt)
{
    NS_LOG_FUNCTION(this << id);
    /// We need to purge the link node cache
    PurgeLinkNode();
    auto i = m_bestRoutesTable_link.find(id);
    if (i == m_bestRoutesTable_link.end())
    {
        NS_LOG_INFO("No route find to " << id);
        return false;
    }
 
    if (i->second.size() < 2)
    {
        NS_LOG_LOGIC("Route to " << id << " error");
        return false;
    }
 
    DsrRouteCacheEntry newEntry; // Create the route entry
    newEntry.SetVector(i->second);
    newEntry.SetDestination(id);
    newEntry.SetExpireTime(RouteCacheTimeout);
    NS_LOG_INFO("Route to " << id << " found with the length " << i->second.size());
    rt = newEntry;
    std::vector<Ipv4Address> path = rt.GetVector();
    PrintVector(path);
    return true;
}
 
void
DsrRouteCache::PurgeLinkNode()
{
    NS_LOG_FUNCTION(this);
    for (auto i = m_linkCache.begin(); i != m_linkCache.end();)
    {
        NS_LOG_DEBUG("The link stability " << i->second.GetLinkStability().As(Time::S));
        auto itmp = i;
        if (i->second.GetLinkStability() <= Seconds(0))
        {
            ++i;
            m_linkCache.erase(itmp);
        }
        else
        {
            ++i;
        }
    }
    /// may need to remove them after verify
    for (auto i = m_nodeCache.begin(); i != m_nodeCache.end();)
    {
        NS_LOG_DEBUG("The node stability " << i->second.GetNodeStability().As(Time::S));
        auto itmp = i;
        if (i->second.GetNodeStability() <= Seconds(0))
        {
            ++i;
            m_nodeCache.erase(itmp);
        }
        else
        {
            ++i;
        }
    }
}
 
void
DsrRouteCache::UpdateNetGraph()
{
    NS_LOG_FUNCTION(this);
    m_netGraph.clear();
    for (auto i = m_linkCache.begin(); i != m_linkCache.end(); ++i)
    {
        // Here the weight is set as 1
        /// \todo May need to set different weight for different link here later
        uint32_t weight = 1;
        m_netGraph[i->first.m_low][i->first.m_high] = weight;
        m_netGraph[i->first.m_high][i->first.m_low] = weight;
    }
}
 
bool
DsrRouteCache::IncStability(Ipv4Address node)
{
    NS_LOG_FUNCTION(this << node);
    auto i = m_nodeCache.find(node);
    if (i == m_nodeCache.end())
    {
        NS_LOG_INFO("The initial stability " << m_initStability.As(Time::S));
        DsrNodeStab ns(m_initStability);
        m_nodeCache[node] = ns;
        return false;
    }
    else
    {
        /// \todo get rid of the debug here
        NS_LOG_INFO("The node stability " << i->second.GetNodeStability().As(Time::S));
        NS_LOG_INFO("The stability here "
                    << Time(i->second.GetNodeStability() * m_stabilityIncrFactor).As(Time::S));
        DsrNodeStab ns(Time(i->second.GetNodeStability() * m_stabilityIncrFactor));
        m_nodeCache[node] = ns;
        return true;
    }
    return false;
}
 
bool
DsrRouteCache::DecStability(Ipv4Address node)
{
    NS_LOG_FUNCTION(this << node);
    auto i = m_nodeCache.find(node);
    if (i == m_nodeCache.end())
    {
        DsrNodeStab ns(m_initStability);
        m_nodeCache[node] = ns;
        return false;
    }
    else
    {
        /// \todo remove it here
        NS_LOG_INFO("The stability here " << i->second.GetNodeStability().As(Time::S));
        NS_LOG_INFO("The stability here "
                    << Time(i->second.GetNodeStability() / m_stabilityDecrFactor).As(Time::S));
        DsrNodeStab ns(Time(i->second.GetNodeStability() / m_stabilityDecrFactor));
        m_nodeCache[node] = ns;
        return true;
    }
    return false;
}
 
bool
DsrRouteCache::AddRoute_Link(DsrRouteCacheEntry::IP_VECTOR nodelist, Ipv4Address source)
{
    NS_LOG_FUNCTION(this << source);
    NS_LOG_LOGIC("Use Link Cache");
    /// Purge the link node cache first
    PurgeLinkNode();
    for (uint32_t i = 0; i < nodelist.size() - 1; i++)
    {
        DsrNodeStab ns; /// This is the node stability
        ns.SetNodeStability(m_initStability);
 
        if (m_nodeCache.find(nodelist[i]) == m_nodeCache.end())
        {
            m_nodeCache[nodelist[i]] = ns;
        }
        if (m_nodeCache.find(nodelist[i + 1]) == m_nodeCache.end())
        {
            m_nodeCache[nodelist[i + 1]] = ns;
        }
        Link link(nodelist[i], nodelist[i + 1]); /// Link represent the one link for the route
        DsrLinkStab stab;                        /// Link stability
        stab.SetLinkStability(m_initStability);
        /// Set the link stability as the smallest node stability
        if (m_nodeCache[nodelist[i]].GetNodeStability() <
            m_nodeCache[nodelist[i + 1]].GetNodeStability())
        {
            stab.SetLinkStability(m_nodeCache[nodelist[i]].GetNodeStability());
        }
        else
        {
            stab.SetLinkStability(m_nodeCache[nodelist[i + 1]].GetNodeStability());
        }
        if (stab.GetLinkStability() < m_minLifeTime)
        {
            NS_LOG_LOGIC("Stability: " << stab.GetLinkStability().As(Time::S));
            /// Set the link stability as the m)minLifeTime, default is 1 second
            stab.SetLinkStability(m_minLifeTime);
        }
        m_linkCache[link] = stab;
        NS_LOG_DEBUG("Add a new link");
        link.Print();
        NS_LOG_DEBUG("Link Info");
        stab.Print();
    }
    UpdateNetGraph();
    RebuildBestRouteTable(source);
    return true;
}
 
void
DsrRouteCache::UseExtends(DsrRouteCacheEntry::IP_VECTOR rt)
{
    NS_LOG_FUNCTION(this);
    /// Purge the link node cache first
    PurgeLinkNode();
    if (rt.size() < 2)
    {
        NS_LOG_INFO("The route is too short");
        return;
    }
    for (auto i = rt.begin(); i != rt.end() - 1; ++i)
    {
        Link link(*i, *(i + 1));
        if (m_linkCache.find(link) != m_linkCache.end())
        {
            if (m_linkCache[link].GetLinkStability() < m_useExtends)
            {
                m_linkCache[link].SetLinkStability(m_useExtends);
                /// \todo remove after debug
                NS_LOG_INFO("The time of the link "
                            << m_linkCache[link].GetLinkStability().As(Time::S));
            }
        }
        else
        {
            NS_LOG_INFO("We cannot find a link in cache");
        }
    }
    /// Increase the stability of the node cache
    for (auto i = rt.begin(); i != rt.end(); ++i)
    {
        if (m_nodeCache.find(*i) != m_nodeCache.end())
        {
            NS_LOG_LOGIC("Increase the stability");
            if (m_nodeCache[*i].GetNodeStability() <= m_initStability)
            {
                IncStability(*i);
            }
            else
            {
                NS_LOG_INFO("The node stability has already been increased");
            }
        }
    }
}
 
bool
DsrRouteCache::AddRoute(DsrRouteCacheEntry& rt)
{
    NS_LOG_FUNCTION(this);
    Purge();
    std::list<DsrRouteCacheEntry> rtVector; // Declare the route cache entry vector
    Ipv4Address dst = rt.GetDestination();
    std::vector<Ipv4Address> route = rt.GetVector();
 
    NS_LOG_DEBUG("The route destination we have " << dst);
    auto i = m_sortedRoutes.find(dst);
 
    if (i == m_sortedRoutes.end())
    {
        rtVector.push_back(rt);
        m_sortedRoutes.erase(dst); // Erase the route entries for dst first
        /**
         * Save the new route cache along with the destination address in map
         */
        auto result = m_sortedRoutes.insert(std::make_pair(dst, rtVector));
        return result.second;
    }
 
    rtVector = i->second;
    NS_LOG_DEBUG("The existing route size " << rtVector.size() << " for destination address "
                                            << dst);
    /**
     * \brief Drop the most aged packet when buffer reaches to max
     */
    if (rtVector.size() >= m_maxEntriesEachDst)
    {
        RemoveLastEntry(rtVector); // Drop the last entry for the sorted route cache, the route
                                   // has already been sorted
    }
 
    if (FindSameRoute(rt, rtVector))
    {
        NS_LOG_DEBUG(
            "Find same vector, the FindSameRoute function will update the route expire time");
        return true;
    }
    else
    {
        // Check if the expire time for the new route has expired or not
        if (rt.GetExpireTime() > Time(0))
        {
            rtVector.push_back(rt);
            // This sort function will sort the route cache entries based on the size of route
            // in each of the route entries
            rtVector.sort(CompareRoutesExpire);
            NS_LOG_DEBUG("The first time" << rtVector.front().GetExpireTime().As(Time::S)
                                          << " The second time "
                                          << rtVector.back().GetExpireTime().As(Time::S));
            NS_LOG_DEBUG("The first hop" << rtVector.front().GetVector().size()
                                         << " The second hop "
                                         << rtVector.back().GetVector().size());
            m_sortedRoutes.erase(dst); // erase the route entries for dst first
            /**
             * Save the new route cache along with the destination address in map
             */
            auto result = m_sortedRoutes.insert(std::make_pair(dst, rtVector));
            return result.second;
        }
        else
        {
            NS_LOG_INFO("The newly found route is already expired");
        }
    }
 
    return false;
}
 
bool
DsrRouteCache::FindSameRoute(DsrRouteCacheEntry& rt, std::list<DsrRouteCacheEntry>& rtVector)
{
    NS_LOG_FUNCTION(this);
    for (auto i = rtVector.begin(); i != rtVector.end(); ++i)
    {
        // return the first route in the route vector
        DsrRouteCacheEntry::IP_VECTOR routeVector = i->GetVector();
        DsrRouteCacheEntry::IP_VECTOR newVector = rt.GetVector();
 
        if (routeVector == newVector)
        {
            NS_LOG_DEBUG("Found same routes in the route cache with the vector size "
                         << rt.GetDestination() << " " << rtVector.size());
            NS_LOG_DEBUG("The new route expire time " << rt.GetExpireTime().As(Time::S)
                                                      << " the original expire time "
                                                      << i->GetExpireTime().As(Time::S));
            if (rt.GetExpireTime() > i->GetExpireTime())
            {
                i->SetExpireTime(rt.GetExpireTime());
            }
            m_sortedRoutes.erase(rt.GetDestination()); // erase the entry first
            rtVector.sort(CompareRoutesExpire);        // sort the route vector first
            /*
             * Save the new route cache along with the destination address in map
             */
            auto result = m_sortedRoutes.insert(std::make_pair(rt.GetDestination(), rtVector));
            return result.second;
        }
    }
    return false;
}
 
bool
DsrRouteCache::DeleteRoute(Ipv4Address dst)
{
    NS_LOG_FUNCTION(this << dst);
    Purge(); // purge the route cache first to remove timeout entries
    if (m_sortedRoutes.erase(dst) != 0)
    {
        NS_LOG_LOGIC("Route deletion to " << dst << " successful");
        return true;
    }
    NS_LOG_LOGIC("Route deletion to " << dst << " not successful");
    return false;
}
 
void
DsrRouteCache::DeleteAllRoutesIncludeLink(Ipv4Address errorSrc,
                                          Ipv4Address unreachNode,
                                          Ipv4Address node)
{
    NS_LOG_FUNCTION(this << errorSrc << unreachNode << node);
    if (IsLinkCache())
    {
        // Purge the link node cache first
        PurgeLinkNode();
        /*
         * The following are for cleaning the broken link in link cache
         * We basically remove the link between errorSrc and unreachNode
         */
        Link link1(errorSrc, unreachNode);
        Link link2(unreachNode, errorSrc);
        // erase the two kind of links to make sure the link is removed from the link cache
        NS_LOG_DEBUG("Erase the route");
        m_linkCache.erase(link1);
        /// \todo get rid of this one
        NS_LOG_DEBUG("The link cache size " << m_linkCache.size());
        m_linkCache.erase(link2);
        NS_LOG_DEBUG("The link cache size " << m_linkCache.size());
 
        auto i = m_nodeCache.find(errorSrc);
        if (i == m_nodeCache.end())
        {
            NS_LOG_LOGIC("Update the node stability unsuccessfully");
        }
        else
        {
            DecStability(i->first);
        }
        i = m_nodeCache.find(unreachNode);
        if (i == m_nodeCache.end())
        {
            NS_LOG_LOGIC("Update the node stability unsuccessfully");
        }
        else
        {
            DecStability(i->first);
        }
        UpdateNetGraph();
        RebuildBestRouteTable(node);
    }
    else
    {
        /*
         * the following are for cleaning the broken link in pathcache
         *
         */
        Purge();
        if (m_sortedRoutes.empty())
        {
            return;
        }
        /*
         * Loop all the routes saved in the route cache
         */
        for (auto j = m_sortedRoutes.begin(); j != m_sortedRoutes.end();)
        {
            auto jtmp = j;
            Ipv4Address address = j->first;
            std::list<DsrRouteCacheEntry> rtVector = j->second;
            /*
             * Loop all the routes for a single destination
             */
            for (auto k = rtVector.begin(); k != rtVector.end();)
            {
                // return the first route in the route vector
                DsrRouteCacheEntry::IP_VECTOR routeVector = k->GetVector();
                DsrRouteCacheEntry::IP_VECTOR changeVector;
                /*
                 * Loop the ip addresses within a single route entry
                 */
                for (auto i = routeVector.begin(); i != routeVector.end(); ++i)
                {
                    if (*i != errorSrc)
                    {
                        changeVector.push_back(*i);
                    }
                    else
                    {
                        changeVector.push_back(*i);
 
                        if (*(i + 1) == unreachNode)
                        {
                            break;
                        }
                    }
                }
                /*
                 * Verify if need to remove some affected links
                 */
                if (changeVector.size() == routeVector.size())
                {
                    NS_LOG_DEBUG("The route does not contain the broken link");
                    ++k;
                }
                else if ((changeVector.size() < routeVector.size()) && (changeVector.size() > 1))
                {
                    NS_LOG_DEBUG("sub route " << m_subRoute);
                    if (m_subRoute)
                    {
                        Time expire = k->GetExpireTime();
                        /*
                         * Remove the route first
                         */
                        k = rtVector.erase(k);
                        DsrRouteCacheEntry changeEntry;
                        changeEntry.SetVector(changeVector);
                        Ipv4Address destination = changeVector.back();
                        NS_LOG_DEBUG("The destination of the newly formed route "
                                     << destination << " and the size of the route "
                                     << changeVector.size());
                        changeEntry.SetDestination(destination);
                        changeEntry.SetExpireTime(
                            expire); // Initialize the timeout value to the one it has
                        rtVector.push_back(changeEntry); // Add the route entry to the route list
                        NS_LOG_DEBUG("We have a sub-route to " << destination);
                    }
                    else
                    {
                        /*
                         * Remove the route
                         */
                        k = rtVector.erase(k);
                    }
                }
                else
                {
                    NS_LOG_LOGIC("Cut route unsuccessful and erase the route");
                    /*
                     * Remove the route
                     */
                    k = rtVector.erase(k);
                }
            }
            ++j;
            if (!IsLinkCache())
            {
                m_sortedRoutes.erase(jtmp);
            }
            if (!rtVector.empty())
            {
                /*
                 * Save the new route cache along with the destination address in map
                 */
                rtVector.sort(CompareRoutesExpire);
                m_sortedRoutes[address] = rtVector;
            }
            else
            {
                NS_LOG_DEBUG("There is no route left for that destination " << address);
            }
        }
    }
}
 
void
DsrRouteCache::PrintVector(std::vector<Ipv4Address>& vec)
{
    NS_LOG_FUNCTION(this);
    /*
     * Check elements in a route vector, used when one wants to check the IP addresses saved in
     */
    if (vec.empty())
    {
        NS_LOG_DEBUG("The vector is empty");
    }
    else
    {
        NS_LOG_DEBUG("Print all the elements in a vector");
        for (auto i = vec.begin(); i != vec.end(); ++i)
        {
            NS_LOG_DEBUG("The ip address " << *i);
        }
    }
}
 
void
DsrRouteCache::PrintRouteVector(std::list<DsrRouteCacheEntry> route)
{
    NS_LOG_FUNCTION(this);
    for (auto i = route.begin(); i != route.end(); i++)
    {
        std::vector<Ipv4Address> path = i->GetVector();
        NS_LOG_INFO("Route NO. ");
        PrintVector(path);
    }
}
 
void
DsrRouteCache::Purge()
{
    NS_LOG_FUNCTION(this);
    // Trying to purge the route cache
    if (m_sortedRoutes.empty())
    {
        NS_LOG_DEBUG("The route cache is empty");
        return;
    }
    for (auto i = m_sortedRoutes.begin(); i != m_sortedRoutes.end();)
    {
        // Loop of route cache entry with the route size
        auto itmp = i;
        /*
         * The route cache entry vector
         */
        Ipv4Address dst = i->first;
        std::list<DsrRouteCacheEntry> rtVector = i->second;
        NS_LOG_DEBUG("The route vector size of 1 " << dst << " " << rtVector.size());
        if (!rtVector.empty())
        {
            for (auto j = rtVector.begin(); j != rtVector.end();)
            {
                NS_LOG_DEBUG("The expire time of every entry with expire time "
                             << j->GetExpireTime());
                /*
                 * First verify if the route has expired or not
                 */
                if (j->GetExpireTime() <= Seconds(0))
                {
                    /*
                     * When the expire time has passed, erase the certain route
                     */
                    NS_LOG_DEBUG("Erase the expired route for " << dst << " with expire time "
                                                                << j->GetExpireTime());
                    j = rtVector.erase(j);
                }
                else
                {
                    ++j;
                }
            }
            NS_LOG_DEBUG("The route vector size of 2 " << dst << " " << rtVector.size());
            if (!rtVector.empty())
            {
                ++i;
                m_sortedRoutes.erase(itmp); // erase the entry first
                /*
                 * Save the new route cache along with the destination address in map
                 */
                m_sortedRoutes.insert(std::make_pair(dst, rtVector));
            }
            else
            {
                ++i;
                m_sortedRoutes.erase(itmp);
            }
        }
        else
        {
            ++i;
            m_sortedRoutes.erase(itmp);
        }
    }
}
 
void
DsrRouteCache::Print(std::ostream& os)
{
    NS_LOG_FUNCTION(this);
    Purge();
    os << "\nDSR Route Cache\n"
       << "Destination\tGateway\t\tInterface\tFlag\tExpire\tHops\n";
    for (auto i = m_routeEntryVector.begin(); i != m_routeEntryVector.end(); ++i)
    {
        i->Print(os);
    }
    os << "\n";
}
 
// ----------------------------------------------------------------------------------------------------------
/**
 * This part of code maintains an Acknowledgment id cache for next hop and remove duplicate ids
 */
uint16_t
DsrRouteCache::CheckUniqueAckId(Ipv4Address nextHop)
{
    NS_LOG_FUNCTION(this);
    auto i = m_ackIdCache.find(nextHop);
    if (i == m_ackIdCache.end())
    {
        NS_LOG_LOGIC("No Ack id for " << nextHop
                                      << " found and use id 1 for the first network ack id");
        m_ackIdCache[nextHop] = 1;
        return 1;
    }
 
    uint16_t ackId = m_ackIdCache[nextHop];
    NS_LOG_LOGIC("Ack id for " << nextHop << " found in the cache has value " << ackId);
    ackId++;
    m_ackIdCache[nextHop] = ackId;
    return ackId;
}
 
uint16_t
DsrRouteCache::GetAckSize()
{
    return m_ackIdCache.size();
}
 
// ----------------------------------------------------------------------------------------------------------
/**
 * This part maintains a neighbor list to handle unidirectional links and link-layer acks
 */
bool
DsrRouteCache::IsNeighbor(Ipv4Address addr)
{
    NS_LOG_FUNCTION(this);
    PurgeMac(); // purge the mac cache
    for (auto i = m_nb.begin(); i != m_nb.end(); ++i)
    {
        if (i->m_neighborAddress == addr)
        {
            return true;
        }
    }
    return false;
}
 
Time
DsrRouteCache::GetExpireTime(Ipv4Address addr)
{
    NS_LOG_FUNCTION(this);
    PurgeMac();
    for (auto i = m_nb.begin(); i != m_nb.end(); ++i)
    {
        if (i->m_neighborAddress == addr)
        {
            return (i->m_expireTime - Simulator::Now());
        }
    }
    return Seconds(0);
}
 
void
DsrRouteCache::UpdateNeighbor(std::vector<Ipv4Address> nodeList, Time expire)
{
    NS_LOG_FUNCTION(this);
    for (auto i = m_nb.begin(); i != m_nb.end(); ++i)
    {
        for (auto j = nodeList.begin(); j != nodeList.end(); ++j)
        {
            if (i->m_neighborAddress == (*j))
            {
                i->m_expireTime = std::max(expire + Simulator::Now(), i->m_expireTime);
                if (i->m_hardwareAddress == Mac48Address())
                {
                    i->m_hardwareAddress = LookupMacAddress(i->m_neighborAddress);
                }
                return;
            }
        }
    }
 
    Ipv4Address addr;
    NS_LOG_LOGIC("Open link to " << addr);
    Neighbor neighbor(addr, LookupMacAddress(addr), expire + Simulator::Now());
    m_nb.push_back(neighbor);
    PurgeMac();
}
 
void
DsrRouteCache::AddNeighbor(std::vector<Ipv4Address> nodeList, Ipv4Address ownAddress, Time expire)
{
    NS_LOG_LOGIC("Add neighbor number " << nodeList.size());
    for (auto j = nodeList.begin(); j != nodeList.end();)
    {
        Ipv4Address addr = *j;
        if (addr == ownAddress)
        {
            j = nodeList.erase(j);
            NS_LOG_DEBUG("The node list size " << nodeList.size());
        }
        else
        {
            ++j;
        }
        Neighbor neighbor(addr, LookupMacAddress(addr), expire + Simulator::Now());
        m_nb.push_back(neighbor);
        PurgeMac();
    }
}
 
/// CloseNeighbor structure
struct CloseNeighbor
{
    /**
     * Check if the entry is expired
     *
     * \param nb DsrRouteCache::Neighbor entry
     * \return true if expired or closed, false otherwise
     */
    bool operator()(const DsrRouteCache::Neighbor& nb) const
    {
        return ((nb.m_expireTime < Simulator::Now()) || nb.close);
    }
};
 
void
DsrRouteCache::PurgeMac()
{
    if (m_nb.empty())
    {
        return;
    }
 
    CloseNeighbor pred;
    if (!m_handleLinkFailure.IsNull())
    {
        for (auto j = m_nb.begin(); j != m_nb.end(); ++j)
        {
            if (pred(*j))
            {
                NS_LOG_LOGIC("Close link to " << j->m_neighborAddress);
                /// \todo disable temporarily
                //              m_handleLinkFailure (j->m_neighborAddress);
            }
        }
    }
    m_nb.erase(std::remove_if(m_nb.begin(), m_nb.end(), pred), m_nb.end());
    m_ntimer.Cancel();
    m_ntimer.Schedule();
}
 
void
DsrRouteCache::ScheduleTimer()
{
    m_ntimer.Cancel();
    m_ntimer.Schedule();
}
 
void
DsrRouteCache::AddArpCache(Ptr<ArpCache> a)
{
    m_arp.push_back(a);
}
 
void
DsrRouteCache::DelArpCache(Ptr<ArpCache> a)
{
    m_arp.erase(std::remove(m_arp.begin(), m_arp.end(), a), m_arp.end());
}
 
Mac48Address
DsrRouteCache::LookupMacAddress(Ipv4Address addr)
{
    Mac48Address hwaddr;
    for (auto i = m_arp.begin(); i != m_arp.end(); ++i)
    {
        ArpCache::Entry* entry = (*i)->Lookup(addr);
        if (entry != nullptr && (entry->IsAlive() || entry->IsPermanent()) && !entry->IsExpired())
        {
            hwaddr = Mac48Address::ConvertFrom(entry->GetMacAddress());
            break;
        }
    }
    return hwaddr;
}
 
void
DsrRouteCache::ProcessTxError(const WifiMacHeader& hdr)
{
    Mac48Address addr = hdr.GetAddr1();
 
    for (auto i = m_nb.begin(); i != m_nb.end(); ++i)
    {
        if (i->m_hardwareAddress == addr)
        {
            i->close = true;
        }
    }
    PurgeMac();
}
} // namespace dsr
} // namespace ns3