#include "random.h"#include "rdt-app.h"// rdtApp OTcl linkage classstatic class rdtAppClass : public TclClass { public:  rdtAppClass() : TclClass("Application/rdtApp") {}  TclObject* create(int, const char*const*) {    return (new rdtApp);  }} class_app_rdt;// When snd_timer_ expires call rdtApp:send_rdt_pkt()void SendTimer::expire(Event*){  t_->send_rdt_pkt();}// When ack_timer_ expires call rdtApp:send_ack_pkt()void AckTimer::expire(Event*){  t_->send_ack_pkt();}// Constructor (also initialize instances of timers)rdtApp::rdtApp() : running_(0), snd_timer_(this), ack_timer_(this){  bind_bw("rate0_", &rate[0]);  bind_bw("rate1_", &rate[1]);  bind_bw("rate2_", &rate[2]);  bind_bw("rate3_", &rate[3]);  bind_bw("rate4_", &rate[4]);  bind("pktsize_", &pktsize_);  bind_bool("random_", &random_);}// OTcl command interpreterint rdtApp::command(int argc, const char*const* argv){  Tcl& tcl = Tcl::instance();  if (argc == 3) {    if (strcmp(argv[1], "attach-agent") == 0) {      agent_ = (Agent*) TclObject::lookup(argv[2]);      if (agent_ == 0) {	tcl.resultf("no such agent %s", argv[2]);	return(TCL_ERROR);      }      // Make sure the underlying agent support MM      if(agent_->supportMM()) {	agent_->enableMM();      }      else {	tcl.resultf("agent \"%s\" does not support rdt Application", argv[2]);	return(TCL_ERROR);      }            agent_->attachApp(this);      return(TCL_OK);    }  }  return (Application::command(argc, argv));}void rdtApp::init(){  rwindow_=7;	//初始化接受方窗口大小  swindow_=7;	//初始化發送方窗口大小  scale_ = 0; // Start at minimum rate  rseq_ = 8;   // rdt sequence number (start from 8) (receiver)  sseq_ = 8;  // rdt sequence number (start from 8) (sender)  lastack_ =8; //the seq of the last ack_pkt  interval_ = (double)(pktsize_ << 3)/(double)rate[scale_];}void rdtApp::start(){  init();  running_ = 1;  send_rdt_pkt();}void rdtApp::stop(){  running_ = 0;}// Send application data packetvoid rdtApp::send_rdt_pkt(){  hdr_rdt mh_buf;  if (running_) {    // the below info is passed to UDPrdt agent, which will write it     // to rdt header after packet creation.    swindow_--;    mh_buf.ack = 0;            // This is not a ack packet    mh_buf.rej = 0;            // This is not a rej packet    mh_buf.seq = ((sseq_++) % 8);         // rdt sequece number    mh_buf.nbytes = pktsize_;  // Size of rdt packet (NOT UDP packet size)    mh_buf.time = Scheduler::instance().clock(); // Current time    mh_buf.scale = scale_;                       // Current scale value    agent_->sendmsg(pktsize_, (char*) &mh_buf);  // send to UDP    // Reschedule the send_pkt timer    double next_time_ = next_snd_time();    if(next_time_ > 0) snd_timer_.resched(next_time_);  }}// Schedule next data packet transmission timedouble rdtApp::next_snd_time(){  // Recompute interval in case rate or size chages  interval_ = (double)(pktsize_ << 3)/(double)rate[scale_];  double next_time_ = interval_;  if(random_)     next_time_ += interval_ * Random::uniform(-0.5, 0.5);  return next_time_;}// Receive message from underlying agentvoid rdtApp::recv_msg(int nbytes, const char *msg){  if(msg) {    hdr_rdt* mh_buf = (hdr_rdt*) msg;	if(mh_buf->ack == 1) {      // If received packet is ACK packet		adjust_swindow(mh_buf);		lastack_ = mh_buf->seq;	        set_scale(mh_buf);	    }	else if( mh_buf ->rej == 1) {	 // If received packet is REJ packet		resend_rdt_pkt(mh_buf);	}	else {      // If received packet is rdt packet		account_recv_pkt(mh_buf);		if(mh_buf->seq == 8) send_ack_pkt();		else if(mh_buf->seq !=((rseq_ + 1) % 8)) {			send_rej_pkt();			}			else {				rseq_= mh_buf ->seq;				rwindow_--;			}	    }  }}void rdtApp::adjust_swindow( const hdr_rdt *mh_buf){	if(swindow_ == 0) {		swindow_ = swindow_ +( (mh_buf->seq + 8 - lastack_ ) % 8);		send_rdt_pkt();	}	else		swindow_ = swindow_ +( (mh_buf->seq + 8 - lastack_ ) % 8);}void rdtApp::adjust_rwindow(void){	rwindow_ = rwindow_ + (( rseq_ - lastack_ ) % 8);}void rdtApp::resend_rdt_pkt( const hdr_rdt *mh_buf){	sseq_ =mh_buf->seq;	send_rdt_pkt();}	void rdtApp::send_ack_pkt(void){  double local_time = Scheduler::instance().clock();  adjust_scale();  // send ack message  hdr_rdt ack_buf;  ack_buf.rej=0;  ack_buf.ack = 1;  // this packet is ack packet  ack_buf.seq= rseq_;  ack_buf.time = local_time;  ack_buf.nbytes = 40;  // Ack packet size is 40 Bytes  ack_buf.scale = p_accnt.last_scale;  adjust_rwindow();  agent_->sendmsg(ack_buf.nbytes, (char*) &ack_buf);  // schedul next ACK time  ack_timer_.resched(p_accnt.rtt);}void rdtApp::send_rej_pkt(void){	  double local_time = Scheduler::instance().clock();  adjust_scale();  // send ack message  hdr_rdt ack_buf;  ack_buf.rej=1;  ack_buf.seq= rseq_;  ack_buf.ack = 0;  // this packet is ack packet  ack_buf.time = local_time;  ack_buf.nbytes = 40;  // Ack packet size is 40 Bytes  ack_buf.scale = p_accnt.last_scale;  agent_->sendmsg(ack_buf.nbytes, (char*) &ack_buf);}// Sender sets its scale to what reciver notifiesvoid rdtApp::set_scale(const hdr_rdt *mh_buf){   scale_ = mh_buf->scale;}void rdtApp::account_recv_pkt(const hdr_rdt *mh_buf){   double local_time = Scheduler::instance().clock();  // Calculate RTT  if(mh_buf->seq == 0) {    init_recv_pkt_accounting();    p_accnt.rtt = 2*(local_time - mh_buf->time);  }  else    p_accnt.rtt = 0.9 * p_accnt.rtt + 0.1 * 2*(local_time - mh_buf->time);   // Count Received packets and Calculate Packet Loss  p_accnt.recv_pkts ++;  p_accnt.lost_pkts += (mh_buf->seq - p_accnt.last_seq - 1);  p_accnt.last_seq = mh_buf->seq;}void rdtApp::init_recv_pkt_accounting(){  p_accnt.last_seq = -1;  p_accnt.last_scale = 0;   p_accnt.lost_pkts = 0;  p_accnt.recv_pkts = 0;}void rdtApp::adjust_scale(void){  if(p_accnt.recv_pkts > 0) {    if(p_accnt.lost_pkts > 0)      p_accnt.last_scale = (int)(p_accnt.last_scale / 2);    else {      p_accnt.last_scale++;      if(p_accnt.last_scale > 4) p_accnt.last_scale = 4;    }  }  p_accnt.recv_pkts = 0;  p_accnt.lost_pkts = 0;}