tcp-abs.cc

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/* -*-  Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
/* tcp-abs.cc
 * Copyright (C) 1999 by USC/ISI
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation, advertising
 * materials, and other materials related to such distribution and use
 * acknowledge that the software was developed by the University of
 * Southern California, Information Sciences Institute.  The name of the
 * University may not be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 * 
 * Contributed by Polly Huang (USC/ISI), http://www-scf.usc.edu/~bhuang
 * @(#) $Header: /nfs/jade/vint/CVSROOT/ns-2/tcp/tcp-abs.cc,v 1.2 1999/05/31 20:40:46 heideman Exp $ (LBL)";
 */

#include "ip.h"
#include "tcp.h"
#include "tcp-abs.h"

//AbsTcp
AbsTcpAgent::AbsTcpAgent() : Agent(PT_TCP), rtt_(0), current_(NULL),offset_(0), seqno_lb_(-1), connection_size_(0), timer_(this), rescheduled_(0)
{
        size_ = 1000;
}

void AbsTcpAgent::timeout()
{
        if (rescheduled_ == 0 && current_->transition_[offset_]!= current_->transition_[0]) {
                set_timer(2*rtt_);
                rescheduled_ = 1;
        } else {
                rescheduled_ = 0;
                seqno_lb_ += current_->batch_size_;
                if (current_->drop_[offset_] == NULL) {
                        printf("Error: This fsm can't handle multi losses per connection\n");
                        exit(0);
                }
                current_ = current_->drop_[offset_];
                send_batch();
        }
}

void AbsTcpAgent::sendmsg(int pktcnt)
{
        connection_size_ = pktcnt;
        start();
}

void AbsTcpAgent::advanceby(int pktcnt)
{
        connection_size_ = pktcnt;
        start();
}

void AbsTcpAgent::start()
{
        //printf("starting fsm tcp, %d\n", connection_size_);
        send_batch();
}

void AbsTcpAgent::send_batch() 
{
        int seqno = seqno_lb_;
        
        offset_ = 0;
        //printf("sending batch, %d\n", current_->batch_size_);
        for (int i=0; i<current_->batch_size_ && seqno < connection_size_-1; i++) {
                seqno++;
                output(seqno);
        }
        if (seqno == connection_size_-1) {
                finish();
        }
        else if (seqno < connection_size_-1) {
                if (current_->drop_[offset_] == NULL) {
                        printf("Error: current fsm can't handle this tcp connection flow id %d (possibly too long)\n", fid_);
                        exit(0);
                } 
                //printf("start timer %d\n", current_->transition_[offset_]);
                if (current_->transition_[offset_] == 0) {
                        current_ = current_->drop_[offset_];
                        send_batch();
                } else if (current_->transition_[offset_] == RTT) {
                        set_timer(rtt_);
                } else if (current_->transition_[offset_] == TIMEOUT) {
                        set_timer(rtt_ * 3);
                } else {
                        printf("Error: weird transition timer\n");
                        exit(0);
                }
        } else {
                printf("Error: sending more than %d packets\n", connection_size_);
                exit(0);
        }
}

void AbsTcpAgent::drop(int seqno)
{
        //printf("dropped: %d\n", seqno);
        if (offset_ != 0) {
                printf("Error: Sorry, can't handle multiple drops per batch\n");
                exit(0);
        }
        offset_ = seqno - seqno_lb_;
        connection_size_++;
}

void AbsTcpAgent::finish()
{
        //printf("finish: sent %d\n", seqno_lb_+1);
        cancel_timer();
}

void AbsTcpAgent::output(int seqno)
{
        Packet* p = allocpkt();
        hdr_tcp *tcph = hdr_tcp::access(p);
        tcph->seqno() = seqno;
        send(p, 0);
}

void AbsTcpAgent::recv(Packet* pkt, Handler*)
{
        Packet::free(pkt);
}

int AbsTcpAgent::command(int argc, const char*const* argv)
{
        if (argc == 3 ) {
                if (strcmp(argv[1], "rtt") == 0) {
                        rtt_ = atof(argv[2]);
                        //printf("rtt %f\n", rtt_);
                        return (TCL_OK);
                }
                if (strcmp(argv[1], "advance") == 0) {
                        advanceby(atoi(argv[2]));
                        return (TCL_OK);
                }
                if (strcmp(argv[1], "advanceby") == 0) {
                        advanceby(atoi(argv[2]));
                        return (TCL_OK);
                }
                if(strcmp(argv[1], "print-stats") == 0) {
                        // xxx: works best if invoked on a new fsm
                        // (otherwise you don't get the whole thing).
                        int n = atoi(argv[2]);
                        if (n < 0 || n >= 17)
                                return TCL_ERROR;
                        FSM::print_FSM_stats(current_, n);
                        return (TCL_OK);
                };
        } else if (argc == 2) {
                if (strcmp(argv[1], "print") == 0) {
                        // xxx: works best if invoked on a new fsm
                        // (otherwise you don't get the whole thing).
                        FSM::print_FSM(current_);
                        return (TCL_OK);
                };
        };
        return (Agent::command(argc, argv));
}

void AbsTcpTimer::expire(Event*)
{
        a_->timeout();
}


//AbsTCP/TahoeAck
static class AbsTcpTahoeAckClass : public TclClass {
public:
        AbsTcpTahoeAckClass() : TclClass("Agent/AbsTCP/TahoeAck") {}
        TclObject* create(int, const char*const*) {
                return (new AbsTcpTahoeAckAgent());
        }
} class_abstcptahoeack;

AbsTcpTahoeAckAgent::AbsTcpTahoeAckAgent() : AbsTcpAgent()
{
        size_ = 1000;
        current_ = TahoeAckFSM::instance().start_state();
        DropTargetAgent::instance().insert_tcp(this);
}


//AbsTCP/RenoAck
static class AbsTcpRenoAckClass : public TclClass {
public:
        AbsTcpRenoAckClass() : TclClass("Agent/AbsTCP/RenoAck") {}
        TclObject* create(int, const char*const*) {
                return (new AbsTcpRenoAckAgent());
        }
} class_abstcprenoack;

AbsTcpRenoAckAgent::AbsTcpRenoAckAgent() : AbsTcpAgent()
{
        size_ = 1000;
        current_ = RenoAckFSM::instance().start_state();
        DropTargetAgent::instance().insert_tcp(this);
}


//AbsTCP/TahoeDelAck
static class AbsTcpTahoeDelAckClass : public TclClass {
public:
        AbsTcpTahoeDelAckClass() : TclClass("Agent/AbsTCP/TahoeDelAck") {}
        TclObject* create(int, const char*const*) {
                return (new AbsTcpTahoeDelAckAgent());
        }
} class_abstcptahoedelack;

AbsTcpTahoeDelAckAgent::AbsTcpTahoeDelAckAgent() : AbsTcpAgent()
{
        size_ = 1000;
        current_ = TahoeDelAckFSM::instance().start_state();
        DropTargetAgent::instance().insert_tcp(this);
}


//AbsTCP/RenoDelAck
static class AbsTcpRenoDelAckClass : public TclClass {
public:
        AbsTcpRenoDelAckClass() : TclClass("Agent/AbsTCP/RenoDelAck") {}
        TclObject* create(int, const char*const*) {
                return (new AbsTcpRenoDelAckAgent());
        }
} class_abstcprenodelack;

AbsTcpRenoDelAckAgent::AbsTcpRenoDelAckAgent() : AbsTcpAgent()
{
        size_ = 1000;
        current_ = RenoDelAckFSM::instance().start_state();
        DropTargetAgent::instance().insert_tcp(this);
}


//AbsTcpSink
static class AbsTcpSinkClass : public TclClass {
public:
        AbsTcpSinkClass() : TclClass("Agent/AbsTCPSink") {}
        TclObject* create(int, const char*const*) {
                return (new AbsTcpSink());
        }
} class_abstcpsink;

AbsTcpSink::AbsTcpSink() : Agent(PT_ACK)
{
        size_ = 40;
}

void AbsTcpSink::recv(Packet* pkt, Handler*)
{
        Packet* p = allocpkt();
        send(p, 0);
        Packet::free(pkt);
}

static class AbsDelAckSinkClass : public TclClass {
public:
        AbsDelAckSinkClass() : TclClass("Agent/AbsTCPSink/DelAck") {}
        TclObject* create(int, const char*const*) {
                return (new AbsDelAckSink());
        }
} class_absdelacksink;

AbsDelAckSink::AbsDelAckSink() : AbsTcpSink(), delay_timer_(this)
{
        size_ = 40;
        interval_ = 0.1;
}

void AbsDelAckSink::recv(Packet* pkt, Handler*)
{
        if (delay_timer_.status() != TIMER_PENDING) {
                delay_timer_.resched(interval_);
        } else {
                delay_timer_.cancel();
                Packet* p = allocpkt();
                send(p, 0);
        }
        Packet::free(pkt);
}

void AbsDelAckSink::timeout()
{
        /*
         * The timer expired so we ACK the last packet seen.
         * (shouldn't this check for a particular time out#?  -kf)
         */
        Packet* p = allocpkt();
        send(p, 0);
}

void AbsDelayTimer::expire(Event */*e*/) {
        a_->timeout();
}

//Special drop target agent
DropTargetAgent* DropTargetAgent::instance_;

static class DropTargetClass : public TclClass {
public:
        DropTargetClass() : TclClass("DropTargetAgent") {}
        TclObject* create(int, const char*const*) {
                return (new DropTargetAgent());
        }
} class_droptarget;

DropTargetAgent::DropTargetAgent(): Connector(), dropper_list_(NULL)
{
        instance_ = this;
}

void DropTargetAgent::recv(Packet* pkt, Handler*)
{
        Dropper* tmp = dropper_list_;

        hdr_tcp *tcph = hdr_tcp::access(pkt);
        hdr_ip *iph = hdr_ip::access(pkt);
        //printf("flow %d dropping seqno %d\n", iph->flowid(),tcph->seqno());
        while(tmp != NULL) {
                if(tmp->agent_->flowid() == iph->flowid())
                        tmp->agent_->drop(tcph->seqno());
                tmp = tmp->next_;
        }
        Packet::free(pkt);
}

void DropTargetAgent::insert_tcp(AbsTcpAgent* tcp)
{
        Dropper* dppr = new Dropper;
        dppr->agent_=tcp;
        dppr->next_ = dropper_list_;
        dropper_list_ = dppr;
}

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