traffictrace.cc

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/* -*-  Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
/*
 * Copyright (c) Xerox Corporation 1997. All rights reserved.
 *  
 * This program 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 2 of the License, or (at your
 * option) any later version.
 *
 * 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.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linking this file statically or dynamically with other modules is making
 * a combined work based on this file.  Thus, the terms and conditions of
 * the GNU General Public License cover the whole combination.
 *
 * In addition, as a special exception, the copyright holders of this file
 * give you permission to combine this file with free software programs or
 * libraries that are released under the GNU LGPL and with code included in
 * the standard release of ns-2 under the Apache 2.0 license or under
 * otherwise-compatible licenses with advertising requirements (or modified
 * versions of such code, with unchanged license).  You may copy and
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 * file and the licenses of the other code concerned, provided that you
 * include the source code of that other code when and as the GNU GPL
 * requires distribution of source code.
 *
 * Note that people who make modified versions of this file are not
 * obligated to grant this special exception for their modified versions;
 * it is their choice whether to do so.  The GNU General Public License
 * gives permission to release a modified version without this exception;
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 * which carries forward this exception.
 */

#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /nfs/jade/vint/CVSROOT/ns-2/trace/traffictrace.cc,v 1.16 2005/08/26 05:05:31 tomh Exp $ (Xerox)";
#endif

/* XXX: have not dealt with errors.  e.g., if something fails during
 * TraceFile::setup(), or TrafficTrace is not pointing to a TraceFile,
 * no guarantee about results.
 */
 
#include <sys/types.h>
#include <sys/stat.h> 
#include <stdio.h>

#include "config.h"
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif /* HAVE_NETINET_IN_H */


#include "random.h"
/* module to implement a traffic generator in ns driven by a trace
 * file.  records in the trace file consist of 2 32 bit fields, the
 * first indicating the inter-packet time in microseconds, and the
 * second indicating the packet length in bytes.  multiple TraffficTrace
 * objects can use the same trace file, and different TrafficTrace
 * objects can use different trace files.  For each TrafficTrace, a
 * random starting point within the trace file is selected.
 */

#include "object.h"
#include "trafgen.h"

struct tracerec {
        u_int32_t trec_time; /* inter-packet time (usec) */
    u_int32_t trec_size; /* size of packet (bytes */
};


/* object to hold a single trace file */

class TraceFile : public NsObject {
 public:
    TraceFile();
    void get_next(int&, struct tracerec&); /* called by TrafficGenerator
                        * to get next record in trace.
                        */
    int setup();  /* initialize the trace file */
    int command(int argc, const char*const* argv);
 private:
    void recv(Packet*, Handler*); /* must be defined for NsObject */
        int status_; 
    char *name_;  /* name of the file in which the trace is stored */
    int nrec_;    /* number of records in the trace file */
    struct tracerec *trace_; /* array holding the trace */
};

/* instance of a traffic generator.  has a pointer to the TraceFile
 * object and implements the interval() function.
 */

class TrafficTrace : public TrafficGenerator {
 public:
    TrafficTrace();
    int command(int argc, const char*const* argv);
    virtual double next_interval(int &);
 protected:
    void timeout();
    TraceFile *tfile_;
    struct tracerec trec_;
    int ndx_;
    void init();
};


static class TraceFileClass : public TclClass {
 public:
    TraceFileClass() : TclClass("Tracefile") {}
    TclObject* create(int, const char*const*) {
        return (new TraceFile());
    }
} class_tracefile;

TraceFile::TraceFile() : status_(0)
{
}

int TraceFile::command(int argc, const char*const* argv)
{

    if (argc == 3) {
        if (strcmp(argv[1], "filename") == 0) {
            name_ = new char[strlen(argv[2])+1];
            strcpy(name_, argv[2]);
            return(TCL_OK);
        }
    }
    return (NsObject::command(argc, argv));
}

void TraceFile::get_next(int& ndx, struct tracerec& t)
{
    t.trec_time = trace_[ndx].trec_time;
    t.trec_size = trace_[ndx].trec_size;

    if (++ndx == nrec_)
        ndx = 0;

}

int TraceFile::setup()
{
    tracerec* t;
    struct stat buf;
    int i;
    FILE *fp;

    /* only open/read the file once (could be shared by multiple
     * SourceModel's
     */
    if (! status_) {
        status_ = 1;

        if (stat(name_, (struct stat *)&buf)) {
            printf("could not stat %s\n", name_);
            return -1;
        }

        nrec_ = buf.st_size/sizeof(tracerec);
        unsigned nrecplus = nrec_ * sizeof(tracerec);
        unsigned bufst = buf.st_size;

        //  if ((unsigned)(nrec_ * sizeof(tracerec)) != buf.st_size) {
        if (nrecplus != bufst) {
            printf("bad file size in %s\n", name_);
            return -1;
        }

        trace_ = new struct tracerec[nrec_];

        if ((fp = fopen(name_, "rb")) == NULL) {
            printf("can't open file %s\n", name_);
            return -1;
        }

        for (i = 0, t = trace_; i < nrec_; i++, t++)
            if (fread((char *)t, sizeof(tracerec), 1, fp) != 1) {
                printf("read failed\n");
                return -1 ;
            }
            else {
        
                t->trec_time = ntohl(t->trec_time);
                t->trec_size = ntohl(t->trec_size);
            }

    }

    /* pick a random starting place in the trace file */
    return (int(Random::uniform((double)nrec_)+.5));

}

void TraceFile::recv(Packet*, Handler*)
{
        /* shouldn't get here */
        abort();
}

/**************************************************************/

static class TrafficTraceClass : public TclClass {
 public:
    TrafficTraceClass() : TclClass("Application/Traffic/Trace") {}
    TclObject* create(int, const char*const*) {
            return(new TrafficTrace());
    }
} class_traffictrace;

TrafficTrace::TrafficTrace()
{
    tfile_ = (TraceFile *)NULL;
}

void TrafficTrace::init()
{
    if (tfile_) 
        ndx_ = tfile_->setup();
}

int TrafficTrace::command(int argc, const char*const* argv)
{
    Tcl& tcl = Tcl::instance();
    
    if (argc == 3) {
        if (strcmp(argv[1], "attach-tracefile") == 0) {
            tfile_ = (TraceFile *)TclObject::lookup(argv[2]);
            if (tfile_ == 0) {
                tcl.resultf("no such node %s", argv[2]);
                return(TCL_ERROR);
            }
            return(TCL_OK);
        }
    }

    return (TrafficGenerator::command(argc, argv));

}

void TrafficTrace::timeout()
{
        if (! running_)
                return;

        /* send a packet */
    // Note:  May need to set "NEW_BURST" flag in sendmsg() for 
    // signifying a new talkspurt when using vat traces.
    // (see expoo.cc, tcl/ex/test-rcvr.tcl)
    agent_->sendmsg(size_);
        /* figure out when to send the next one */
        nextPkttime_ = next_interval(size_);
        /* schedule it */
        timer_.resched(nextPkttime_);
}


double TrafficTrace::next_interval(int& size)
{
        tfile_->get_next(ndx_, trec_);
    size = trec_.trec_size;
    return(((double)trec_.trec_time)/1000000.0); /* usecs->secs */
}

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