rtcp.cc

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/* -*-  Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*-
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 * Copyright (c) 1997 Regents of the University of California.
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 *  This product includes software developed by the MASH Research
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#ifndef lint
static const char rcsid[] =
    "@(#) $Header: /nfs/jade/vint/CVSROOT/ns-2/tcp/rtcp.cc,v 1.17 2000/09/01 03:04:06 haoboy Exp $";
#endif

#include <stdlib.h>

#include "config.h"
#include "agent.h"
#include "random.h"
#include "rtp.h"

class RTCPAgent;

class RTCP_Timer : public TimerHandler {
public: 
    RTCP_Timer(RTCPAgent *a) : TimerHandler() { a_ = a; }
protected:
    virtual void expire(Event *e);
    RTCPAgent *a_;
};

class RTCPAgent : public Agent {
public:
    RTCPAgent();
    virtual void timeout(int);
    virtual void recv(Packet* p, Handler* h);
    int command(int argc, const char*const* argv);
protected:
    void start();
    void stop();
    void sendpkt();

    int running_;
    int random_;
    int seqno_;
    double interval_;
    RTPSession* session_;

    RTCP_Timer rtcp_timer_;
};

static class RTCPAgentClass : public TclClass {
public:
    RTCPAgentClass() : TclClass("Agent/RTCP") {}
    TclObject* create(int, const char*const*) {
        return (new RTCPAgent());
    }
} class_rtcp_agent;

/* XXX Could perhaps derive this from CBR.  If so, use cbr_timer_ */
RTCPAgent::RTCPAgent()
    : Agent(PT_RTCP), session_(0), rtcp_timer_(this)
{
    size_ = 128;
    bind_time("interval_", &interval_);
    bind("random_", &random_);
    bind("seqno_", &seqno_);
    running_ = 0;
}

void RTCPAgent::start()
{
    running_ = 1;
    rtcp_timer_.resched(interval_);
}

void RTCPAgent::stop()
{
    rtcp_timer_.cancel();
    running_ = 0;
}

void RTCPAgent::recv(Packet* p, Handler*)
{
    session_->recv_ctrl(p);
}

void RTCPAgent::sendpkt()
{
    Packet* p = allocpkt();
    hdr_rtp* rh = hdr_rtp::access(p);

    /* Fill in srcid_ and seqno */
    rh->seqno() = seqno_++;
    rh->srcid() = session_->srcid();
    target_->recv(p);
}

void RTCPAgent::timeout(int)
{
    if (running_) {
        size_ = session_->build_report(0);
        sendpkt();
        double t = interval_;
        if (random_)
            /* add some zero-mean white noise */
            t += interval_ * Random::uniform(-0.5, 0.5);    
        rtcp_timer_.resched(t);
        /* XXX */
        Tcl::instance().evalf("%s rtcp_timeout", session_->name());
    }
}

int RTCPAgent::command(int argc, const char*const* argv)
{
    if (argc == 2) {
        if (strcmp(argv[1], "start") == 0) {
            start();
            return (TCL_OK);
        }
        if (strcmp(argv[1], "stop") == 0) {
            stop();
            return (TCL_OK);
        }
        if (strcmp(argv[1], "bye") == 0) {
            size_ = session_->build_report(1);
            sendpkt();
            stop();
            return (TCL_OK);
        }
    } else if (argc == 3) {
        if (strcmp(argv[1], "session") == 0) {
            session_ = (RTPSession*)TclObject::lookup(argv[2]);
            return (TCL_OK);
        }
    }

    return (Agent::command(argc, argv));
}

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

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