/* -*-	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
 * distribute such a system following the terms of the GNU GPL for this
 * 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;
 * this exception also makes it possible to release a modified version
 * which carries forward this exception.
 *
 * $Header: /cvsroot/nsnam/ns-2/adc/sa.cc,v 1.16 2005/08/26 05:05:28 tomh Exp $
 */

//packets after it succeeds in a3-way handshake from the receiver
// should be connected with Agent/SignalAck class

#include "udp.h"
#include "sa.h"
#include "ip.h"
#include "random.h"

#define SAMPLERATE 8000

SA_Agent::SA_Agent() : Agent(PT_UDP), trafgen_(0), rtd_(0), callback_(0), 
    sa_timer_(this), nextPkttime_(-1), running_(0), seqno_(-1)
{
	bind_bw("rate_",&rate_);
	bind("bucket_",&bucket_);
	bind("packetSize_", &size_);
}

SA_Agent::~SA_Agent()
{
        if (callback_) 
                delete[] callback_;

}


static class SA_AgentClass : public TclClass {
public:
	SA_AgentClass() : TclClass("Agent/SA") {}
	TclObject* create(int, const char*const*) {
		return (new SA_Agent());
	}
} class_signalsource_agent;

int SA_Agent::command(int argc, const char*const* argv)
{
	Tcl& tcl = Tcl::instance();
	if (argc==3) {
		if (strcmp(argv[1], "target") == 0) {
			target_ = (NsObject*)TclObject::lookup(argv[2]);
			if (target_ == 0) {
				tcl.resultf("no such object %s", argv[2]);
				return (TCL_ERROR);
			}
			ctrl_target_=target_;
			return (TCL_OK);
		} 
		else if (strcmp(argv[1],"ctrl-target")== 0) {
			ctrl_target_=(NsObject*)TclObject::lookup(argv[2]);
			if (ctrl_target_ == 0) {
				tcl.resultf("no such object %s", argv[2]);
				return (TCL_ERROR);
			}
			return (TCL_OK);
		}
	        if (strcmp(argv[1], "stoponidle") == 0) {
		        stoponidle(argv[2]);
			return(TCL_OK);
		}
                if (strcmp(argv[1], "attach-traffic") == 0) {
                        trafgen_ =(TrafficGenerator*)TclObject::lookup(argv[2]);
                        if (trafgen_ == 0) {
                                tcl.resultf("no such node %s", argv[2]);
                                return(TCL_ERROR);
                        }
                        return(TCL_OK);
                }

	}
        if (argc == 2) {
                if (strcmp(argv[1], "start") == 0) {
                        start();
                        return(TCL_OK);
                } else if (strcmp(argv[1], "stop") == 0) {
                        stop();
                        return(TCL_OK);
                }
        }
	return (Agent::command(argc,argv));
}


void SA_Agent::start()
{
	//send the request packet
	if (trafgen_) {
		trafgen_->init();
		//running_=1;
		sendreq();
	}
}

void SA_Agent::stop()
{
	sendteardown();
	if (running_ != 0) {
		sa_timer_.cancel();
		running_ =0;
	}
}


void SA_Agent::sendreq()
{
	Packet *p = allocpkt();
	hdr_cmn* ch= hdr_cmn::access(p);
	ch->ptype()=PT_REQUEST;
	ch->size()=20;
	//also put in the r,b parameters for the flow in the packet
	hdr_resv* rv=hdr_resv::access(p);
	rv->decision() =1;
	rv->rate()=rate_;
	rv->bucket()=bucket_;
	ctrl_target_->recv(p);
}

void SA_Agent::sendteardown()
{
	Packet *p = allocpkt();
	hdr_cmn* ch= hdr_cmn::access(p);
	ch->ptype()=PT_TEARDOWN;
	ch->size()=20;
	//also put in the r,b parameters for the flow in the packet
	hdr_resv* rv=hdr_resv::access(p);
	rv->decision() =1;
	rv->rate()=rate_;
	rv->bucket()=bucket_;
	ctrl_target_->recv(p);
}


void SA_Agent::recv(Packet *p, Handler *) 
{
	hdr_cmn *ch= hdr_cmn::access(p);
	hdr_resv *rv=hdr_resv::access(p);
	hdr_ip * iph = hdr_ip::access(p);
	if ( ch->ptype() == PT_ACCEPT || ch->ptype() == PT_REJECT ) {
		ch->ptype() = PT_CONFIRM;

		// turn the packet around by swapping src and dst
		// (address and port)
		ns_addr_t tmp;
		tmp = iph->src();
		iph->src() = iph->dst();
		iph->dst() = tmp;
		ctrl_target_->recv(p);
	}
	
	// put an additional check here to see if admission was granted
	if (rv->decision()) {
		//printf("Flow %d accepted @ %f\n",iph->flowid(),Scheduler::instance().clock());
		fflush(stdout);
		double t = trafgen_->next_interval(size_);
		running_=1;
		sa_timer_.resched(t);
	}
	else {
		//printf("Flow %d rejected @ %f\n",iph->flowid(),Scheduler::instance().clock());
		fflush(stdout);
		//Currently the flow is stopped if rejected
		running_=0;
	}
	//make an upcall to sched a stoptime for this flow from now
	Tcl::instance().evalf("%s sched-stop %d",name(),rv->decision());
}

void SA_Agent::stoponidle(const char *s)
{
        callback_ = new char[strlen(s)+1];
        strcpy(callback_, s);

        if (trafgen_->on()) {
                // Tcl::instance().evalf("puts \"%s waiting for burst at %f\"", name(), Scheduler::instance().clock());
                rtd_ = 1;
        }
        else {
                stop();
                Tcl::instance().evalf("%s %s", name(), callback_);
        }

}

void SA_Timer::expire(Event* /*e*/) {
        a_->timeout(0);
}

void SA_Agent::timeout(int)
{
        if (running_) {
                /* send a packet */
                sendpkt();
                /* figure out when to send the next one */
                nextPkttime_ = trafgen_->next_interval(size_);
                /* schedule it */
                sa_timer_.resched(nextPkttime_);

                /* hack: if we are waiting for a current burst to end
                 * before stopping . . .
                 */
                if (rtd_) {
                        if (trafgen_->on() == 0) {
                                stop();
                                //Tcl::instance().evalf("puts \"%s burst over at %f\"",
                                // name(), Scheduler::instance().clock());
                                Tcl::instance().evalf("%s sched-stop %d", name(), 0);
                        }
                }
        }
}

void SA_Agent::sendpkt()
{
        Packet* p = allocpkt();
        hdr_rtp* rh = hdr_rtp::access(p);
        rh->seqno() = ++seqno_;
        rh->flags()=0;

        double local_time=Scheduler::instance().clock();
        /*put in "rtp timestamps" and begining of talkspurt labels */
        hdr_cmn* ch = hdr_cmn::access(p);
        ch->timestamp()=(u_int32_t)(SAMPLERATE*local_time);
        ch->size()=size_;
        if ((nextPkttime_ != trafgen_->interval()) || (nextPkttime_ == -1))
                rh->flags() |= RTP_M;

        target_->recv(p);
}

void SA_Agent::sendmsg(int nbytes, const char* /*flags*/)
{
        Packet *p;
        int n;

	assert (size_ > 0);

	n = nbytes / size_;

        if (nbytes == -1) {
                start();
                return;
        }
        while (n-- > 0) {
       		p = allocpkt();
                hdr_rtp* rh = hdr_rtp::access(p);
                rh->seqno() = seqno_;
                target_->recv(p);
        }
        n = nbytes % size_;
        if (n > 0) {
        	p = allocpkt();
        	hdr_rtp* rh = hdr_rtp::access(p);
        	rh->seqno() = seqno_;
        	target_->recv(p);
        }
        idle();
}