/*
 * Copyright (c) 2002-2005 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Nathan Binkert
 *          Ron Dreslinski
 */

/* @file
 * Device module for modelling a fixed bandwidth full duplex ethernet link
 */

#include <cmath>
#include <deque>
#include <string>
#include <vector>

#include "base/random.hh"
#include "base/trace.hh"
#include "dev/etherdump.hh"
#include "dev/etherint.hh"
#include "dev/etherlink.hh"
#include "dev/etherpkt.hh"
#include "sim/builder.hh"
#include "sim/serialize.hh"
#include "sim/system.hh"
#include "sim/core.hh"

using namespace std;

EtherLink::EtherLink(const string &name, EtherInt *peer0, EtherInt *peer1,
                     double rate, Tick delay, Tick delayVar, EtherDump *dump)
    : SimObject(name)
{
    link[0] = new Link(name + ".link0", this, 0, rate, delay, delayVar, dump);
    link[1] = new Link(name + ".link1", this, 1, rate, delay, delayVar, dump);

    interface[0] = new Interface(name + ".int0", link[0], link[1]);
    interface[1] = new Interface(name + ".int1", link[1], link[0]);

    interface[0]->setPeer(peer0);
    peer0->setPeer(interface[0]);
    interface[1]->setPeer(peer1);
    peer1->setPeer(interface[1]);
}

EtherLink::~EtherLink()
{
    delete link[0];
    delete link[1];

    delete interface[0];
    delete interface[1];
}

EtherLink::Interface::Interface(const string &name, Link *tx, Link *rx)
    : EtherInt(name), txlink(tx)
{
    tx->setTxInt(this);
    rx->setRxInt(this);
}

EtherLink::Link::Link(const string &name, EtherLink *p, int num,
                      double rate, Tick delay, Tick delay_var, EtherDump *d)
    : objName(name), parent(p), number(num), txint(NULL), rxint(NULL),
      ticksPerByte(rate), linkDelay(delay), delayVar(delay_var), dump(d),
      doneEvent(this)
{ }

void
EtherLink::serialize(ostream &os)
{
    link[0]->serialize("link0", os);
    link[1]->serialize("link1", os);
}

void
EtherLink::unserialize(Checkpoint *cp, const string &section)
{
    link[0]->unserialize("link0", cp, section);
    link[1]->unserialize("link1", cp, section);
}

void
EtherLink::Link::txComplete(EthPacketPtr packet)
{
    DPRINTF(Ethernet, "packet received: len=%d\n", packet->length);
    DDUMP(EthernetData, packet->data, packet->length);
    rxint->sendPacket(packet);
}

class LinkDelayEvent : public Event
{
  protected:
    EtherLink::Link *link;
    EthPacketPtr packet;

  public:
    // non-scheduling version for createForUnserialize()
    LinkDelayEvent();
    LinkDelayEvent(EtherLink::Link *link, EthPacketPtr pkt, Tick when);

    void process();

    virtual void serialize(ostream &os);
    virtual void unserialize(Checkpoint *cp, const string &section);
    static Serializable *createForUnserialize(Checkpoint *cp,
                                              const string &section);
};

void
EtherLink::Link::txDone()
{
    if (dump)
        dump->dump(packet);

    if (linkDelay > 0) {
        DPRINTF(Ethernet, "packet delayed: delay=%d\n", linkDelay);
        new LinkDelayEvent(this, packet, curTick + linkDelay);
    } else {
        txComplete(packet);
    }

    packet = 0;
    assert(!busy());

    txint->sendDone();
}

bool
EtherLink::Link::transmit(EthPacketPtr pkt)
{
    if (busy()) {
        DPRINTF(Ethernet, "packet not sent, link busy\n");
        return false;
    }

    DPRINTF(Ethernet, "packet sent: len=%d\n", pkt->length);
    DDUMP(EthernetData, pkt->data, pkt->length);

    packet = pkt;
    Tick delay = (Tick)ceil(((double)pkt->length * ticksPerByte) + 1.0);
    if (delayVar != 0) {
        Random<Tick> var;
        delay +=  var.uniform(0, delayVar);
    }
    DPRINTF(Ethernet, "scheduling packet: delay=%d, (rate=%f)\n",
            delay, ticksPerByte);
    doneEvent.schedule(curTick + delay);

    return true;
}

void
EtherLink::Link::serialize(const string &base, ostream &os)
{
    bool packet_exists = packet;
    paramOut(os, base + ".packet_exists", packet_exists);
    if (packet_exists)
        packet->serialize(base + ".packet", os);

    bool event_scheduled = doneEvent.scheduled();
    paramOut(os, base + ".event_scheduled", event_scheduled);
    if (event_scheduled) {
        Tick event_time = doneEvent.when();
        paramOut(os, base + ".event_time", event_time);
    }

}

void
EtherLink::Link::unserialize(const string &base, Checkpoint *cp,
                             const string &section)
{
    bool packet_exists;
    paramIn(cp, section, base + ".packet_exists", packet_exists);
    if (packet_exists) {
        packet = new EthPacketData(16384);
        packet->unserialize(base + ".packet", cp, section);
    }

    bool event_scheduled;
    paramIn(cp, section, base + ".event_scheduled", event_scheduled);
    if (event_scheduled) {
        Tick event_time;
        paramIn(cp, section, base + ".event_time", event_time);
        doneEvent.schedule(event_time);
    }
}

LinkDelayEvent::LinkDelayEvent()
    : Event(&mainEventQueue), link(NULL)
{
    setFlags(AutoSerialize);
    setFlags(AutoDelete);
}

LinkDelayEvent::LinkDelayEvent(EtherLink::Link *l, EthPacketPtr p, Tick when)
    : Event(&mainEventQueue), link(l), packet(p)
{
    setFlags(AutoSerialize);
    setFlags(AutoDelete);
    schedule(when);
}

void
LinkDelayEvent::process()
{
    link->txComplete(packet);
}

void
LinkDelayEvent::serialize(ostream &os)
{
    paramOut(os, "type", string("LinkDelayEvent"));
    Event::serialize(os);

    EtherLink *parent = link->parent;
    bool number = link->number;
    SERIALIZE_OBJPTR(parent);
    SERIALIZE_SCALAR(number);

    packet->serialize("packet", os);
}


void
LinkDelayEvent::unserialize(Checkpoint *cp, const string &section)
{
    Event::unserialize(cp, section);

    EtherLink *parent;
    bool number;
    UNSERIALIZE_OBJPTR(parent);
    UNSERIALIZE_SCALAR(number);

    link = parent->link[number];

    packet = new EthPacketData(16384);
    packet->unserialize("packet", cp, section);
}


Serializable *
LinkDelayEvent::createForUnserialize(Checkpoint *cp, const string &section)
{
    return new LinkDelayEvent();
}

REGISTER_SERIALIZEABLE("LinkDelayEvent", LinkDelayEvent)

BEGIN_DECLARE_SIM_OBJECT_PARAMS(EtherLink)

    SimObjectParam<EtherInt *> int1;
    SimObjectParam<EtherInt *> int2;
    Param<double> speed;
    Param<Tick> delay;
    Param<Tick> delay_var;
    SimObjectParam<EtherDump *> dump;

END_DECLARE_SIM_OBJECT_PARAMS(EtherLink)

BEGIN_INIT_SIM_OBJECT_PARAMS(EtherLink)

    INIT_PARAM(int1, "interface 1"),
    INIT_PARAM(int2, "interface 2"),
    INIT_PARAM(speed, "link speed in bits per second"),
    INIT_PARAM(delay, "transmit delay of packets in us"),
    INIT_PARAM(delay_var, "Difference in amount of time to traverse wire"),
    INIT_PARAM(dump, "object to dump network packets to")

END_INIT_SIM_OBJECT_PARAMS(EtherLink)

CREATE_SIM_OBJECT(EtherLink)
{
    return new EtherLink(getInstanceName(), int1, int2, speed, delay, delay_var,
                         dump);
}

REGISTER_SIM_OBJECT("EtherLink", EtherLink)