/*
 * Copyright (c) 2016 Universita' di Firenze, Italy
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Tommaso Pecorella <tommaso.pecorella@unifi.it>
 */

// Network topology
//
//    SRC
//     |<=== source network
//     A-----B
//      \   / \   all networks have cost 1, except
//       \ /  |   for the direct link from C to D, which
//        C  /    has cost 10
//        | /
//        |/
//        D
//        |<=== target network
//       DST
//
//
// A, B, C and D are RIPng routers.
// A and D are configured with static addresses.
// SRC and DST will exchange packets.
//
// After about 3 seconds, the topology is built, and Echo Reply will be received.
// After 40 seconds, the link between B and D will break, causing a route failure.
// After 44 seconds from the failure, the routers will recovery from the failure.
// Split Horizoning should affect the recovery time, but it is not. See the manual
// for an explanation of this effect.
//
// If "showPings" is enabled, the user will see:
// 1) if the ping has been acknowledged
// 2) if a Destination Unreachable has been received by the sender
// 3) nothing, when the Echo Request has been received by the destination but
//    the Echo Reply is unable to reach the sender.
// Examining the .pcap files with Wireshark can confirm this effect.

#include "ns3/core-module.h"
#include "ns3/csma-module.h"
#include "ns3/internet-apps-module.h"
#include "ns3/internet-module.h"
#include "ns3/ipv4-routing-table-entry.h"
#include "ns3/ipv4-static-routing-helper.h"

#include <fstream>

using namespace ns3;

NS_LOG_COMPONENT_DEFINE("RipSimpleRouting");

void
TearDownLink(Ptr<Node> nodeA, Ptr<Node> nodeB, uint32_t interfaceA, uint32_t interfaceB)
{
    nodeA->GetObject<Ipv4>()->SetDown(interfaceA);
    nodeB->GetObject<Ipv4>()->SetDown(interfaceB);
}

int
main(int argc, char** argv)
{
    bool verbose = false;
    bool printRoutingTables = false;
    bool showPings = false;
    std::string SplitHorizon("PoisonReverse");

    CommandLine cmd(__FILE__);
    cmd.AddValue("verbose", "turn on log components", verbose);
    cmd.AddValue("printRoutingTables",
                 "Print routing tables at 30, 60 and 90 seconds",
                 printRoutingTables);
    cmd.AddValue("showPings", "Show Ping6 reception", showPings);
    cmd.AddValue("splitHorizonStrategy",
                 "Split Horizon strategy to use (NoSplitHorizon, SplitHorizon, PoisonReverse)",
                 SplitHorizon);
    cmd.Parse(argc, argv);

    if (verbose)
    {
        LogComponentEnableAll(LogLevel(LOG_PREFIX_TIME | LOG_PREFIX_NODE));
        LogComponentEnable("RipSimpleRouting", LOG_LEVEL_INFO);
        LogComponentEnable("Rip", LOG_LEVEL_ALL);
        LogComponentEnable("Ipv4Interface", LOG_LEVEL_ALL);
        LogComponentEnable("Icmpv4L4Protocol", LOG_LEVEL_ALL);
        LogComponentEnable("Ipv4L3Protocol", LOG_LEVEL_ALL);
        LogComponentEnable("ArpCache", LOG_LEVEL_ALL);
        LogComponentEnable("V4Ping", LOG_LEVEL_ALL);
    }

    if (SplitHorizon == "NoSplitHorizon")
    {
        Config::SetDefault("ns3::Rip::SplitHorizon", EnumValue(RipNg::NO_SPLIT_HORIZON));
    }
    else if (SplitHorizon == "SplitHorizon")
    {
        Config::SetDefault("ns3::Rip::SplitHorizon", EnumValue(RipNg::SPLIT_HORIZON));
    }
    else
    {
        Config::SetDefault("ns3::Rip::SplitHorizon", EnumValue(RipNg::POISON_REVERSE));
    }

    NS_LOG_INFO("Create nodes.");
    Ptr<Node> src = CreateObject<Node>();
    Names::Add("SrcNode", src);
    Ptr<Node> dst = CreateObject<Node>();
    Names::Add("DstNode", dst);
    Ptr<Node> a = CreateObject<Node>();
    Names::Add("RouterA", a);
    Ptr<Node> b = CreateObject<Node>();
    Names::Add("RouterB", b);
    Ptr<Node> c = CreateObject<Node>();
    Names::Add("RouterC", c);
    Ptr<Node> d = CreateObject<Node>();
    Names::Add("RouterD", d);
    NodeContainer net1(src, a);
    NodeContainer net2(a, b);
    NodeContainer net3(a, c);
    NodeContainer net4(b, c);
    NodeContainer net5(c, d);
    NodeContainer net6(b, d);
    NodeContainer net7(d, dst);
    NodeContainer routers(a, b, c, d);
    NodeContainer nodes(src, dst);

    NS_LOG_INFO("Create channels.");
    CsmaHelper csma;
    csma.SetChannelAttribute("DataRate", DataRateValue(5000000));
    csma.SetChannelAttribute("Delay", TimeValue(MilliSeconds(2)));
    NetDeviceContainer ndc1 = csma.Install(net1);
    NetDeviceContainer ndc2 = csma.Install(net2);
    NetDeviceContainer ndc3 = csma.Install(net3);
    NetDeviceContainer ndc4 = csma.Install(net4);
    NetDeviceContainer ndc5 = csma.Install(net5);
    NetDeviceContainer ndc6 = csma.Install(net6);
    NetDeviceContainer ndc7 = csma.Install(net7);

    NS_LOG_INFO("Create IPv4 and routing");
    RipHelper ripRouting;

    // Rule of thumb:
    // Interfaces are added sequentially, starting from 0
    // However, interface 0 is always the loopback...
    ripRouting.ExcludeInterface(a, 1);
    ripRouting.ExcludeInterface(d, 3);

    ripRouting.SetInterfaceMetric(c, 3, 10);
    ripRouting.SetInterfaceMetric(d, 1, 10);

    Ipv4ListRoutingHelper listRH;
    listRH.Add(ripRouting, 0);
    //  Ipv4StaticRoutingHelper staticRh;
    //  listRH.Add (staticRh, 5);

    InternetStackHelper internet;
    internet.SetIpv6StackInstall(false);
    internet.SetRoutingHelper(listRH);
    internet.Install(routers);

    InternetStackHelper internetNodes;
    internetNodes.SetIpv6StackInstall(false);
    internetNodes.Install(nodes);

    // Assign addresses.
    // The source and destination networks have global addresses
    // The "core" network just needs link-local addresses for routing.
    // We assign global addresses to the routers as well to receive
    // ICMPv6 errors.
    NS_LOG_INFO("Assign IPv4 Addresses.");
    Ipv4AddressHelper ipv4;

    ipv4.SetBase(Ipv4Address("10.0.0.0"), Ipv4Mask("255.255.255.0"));
    Ipv4InterfaceContainer iic1 = ipv4.Assign(ndc1);

    ipv4.SetBase(Ipv4Address("10.0.1.0"), Ipv4Mask("255.255.255.0"));
    Ipv4InterfaceContainer iic2 = ipv4.Assign(ndc2);

    ipv4.SetBase(Ipv4Address("10.0.2.0"), Ipv4Mask("255.255.255.0"));
    Ipv4InterfaceContainer iic3 = ipv4.Assign(ndc3);

    ipv4.SetBase(Ipv4Address("10.0.3.0"), Ipv4Mask("255.255.255.0"));
    Ipv4InterfaceContainer iic4 = ipv4.Assign(ndc4);

    ipv4.SetBase(Ipv4Address("10.0.4.0"), Ipv4Mask("255.255.255.0"));
    Ipv4InterfaceContainer iic5 = ipv4.Assign(ndc5);

    ipv4.SetBase(Ipv4Address("10.0.5.0"), Ipv4Mask("255.255.255.0"));
    Ipv4InterfaceContainer iic6 = ipv4.Assign(ndc6);

    ipv4.SetBase(Ipv4Address("10.0.6.0"), Ipv4Mask("255.255.255.0"));
    Ipv4InterfaceContainer iic7 = ipv4.Assign(ndc7);

    Ptr<Ipv4StaticRouting> staticRouting;
    staticRouting = Ipv4RoutingHelper::GetRouting<Ipv4StaticRouting>(
        src->GetObject<Ipv4>()->GetRoutingProtocol());
    staticRouting->SetDefaultRoute("10.0.0.2", 1);
    staticRouting = Ipv4RoutingHelper::GetRouting<Ipv4StaticRouting>(
        dst->GetObject<Ipv4>()->GetRoutingProtocol());
    staticRouting->SetDefaultRoute("10.0.6.1", 1);

    if (printRoutingTables)
    {
        RipHelper routingHelper;

        Ptr<OutputStreamWrapper> routingStream = Create<OutputStreamWrapper>(&std::cout);

        routingHelper.PrintRoutingTableAt(Seconds(30.0), a, routingStream);
        routingHelper.PrintRoutingTableAt(Seconds(30.0), b, routingStream);
        routingHelper.PrintRoutingTableAt(Seconds(30.0), c, routingStream);
        routingHelper.PrintRoutingTableAt(Seconds(30.0), d, routingStream);

        routingHelper.PrintRoutingTableAt(Seconds(60.0), a, routingStream);
        routingHelper.PrintRoutingTableAt(Seconds(60.0), b, routingStream);
        routingHelper.PrintRoutingTableAt(Seconds(60.0), c, routingStream);
        routingHelper.PrintRoutingTableAt(Seconds(60.0), d, routingStream);

        routingHelper.PrintRoutingTableAt(Seconds(90.0), a, routingStream);
        routingHelper.PrintRoutingTableAt(Seconds(90.0), b, routingStream);
        routingHelper.PrintRoutingTableAt(Seconds(90.0), c, routingStream);
        routingHelper.PrintRoutingTableAt(Seconds(90.0), d, routingStream);
    }

    NS_LOG_INFO("Create Applications.");
    uint32_t packetSize = 1024;
    Time interPacketInterval = Seconds(1.0);
    V4PingHelper ping("10.0.6.2");

    ping.SetAttribute("Interval", TimeValue(interPacketInterval));
    ping.SetAttribute("Size", UintegerValue(packetSize));
    if (showPings)
    {
        ping.SetAttribute("Verbose", BooleanValue(true));
    }
    ApplicationContainer apps = ping.Install(src);
    apps.Start(Seconds(1.0));
    apps.Stop(Seconds(110.0));

    AsciiTraceHelper ascii;
    csma.EnableAsciiAll(ascii.CreateFileStream("rip-simple-routing.tr"));
    csma.EnablePcapAll("rip-simple-routing", true);

    Simulator::Schedule(Seconds(40), &TearDownLink, b, d, 3, 2);

    /* Now, do the actual simulation. */
    NS_LOG_INFO("Run Simulation.");
    Simulator::Stop(Seconds(131.0));
    Simulator::Run();
    Simulator::Destroy();
    NS_LOG_INFO("Done.");

    return 0;
}