StopWaitRdtSender.cpp

#include "stdafx.h"
#ifndef NONE_STOP_WAIT_RDT_SENDER_MODE
#include "Global.h"
#include "StopWaitRdtSender.h"

	StopWaitRdtSender::StopWaitRdtSender():expectSequenceNumberSend(0),waitingState(false)
	{
	}


	StopWaitRdtSender::~StopWaitRdtSender()
	{
	}



	bool StopWaitRdtSender::getWaitingState() {
		return waitingState;
	}




	bool StopWaitRdtSender::send(const Message &message) {
		if (this->waitingState) { //发送方处于等待确认状态
			return false;
		}
	
		this->packetWaitingAck.acknum = -1; //忽略该字段
		this->packetWaitingAck.seqnum = this->expectSequenceNumberSend;
		this->packetWaitingAck.checksum = 0;
		memcpy(this->packetWaitingAck.payload, message.data, sizeof(message.data));
		this->packetWaitingAck.checksum = pUtils->calculateCheckSum(this->packetWaitingAck);
		pUtils->printPacket("发送方发送报文", this->packetWaitingAck);
		pns->startTimer(SENDER, Configuration::TIME_OUT,this->packetWaitingAck.seqnum);			//启动发送方定时器
		pns->sendToNetworkLayer(RECEIVER, this->packetWaitingAck);								//调用模拟网络环境的sendToNetworkLayer，通过网络层发送到对方

		this->waitingState = true;																					//进入等待状态
		return true;
	}

	void StopWaitRdtSender::receive(const Packet &ackPkt) {
		if (this->waitingState == true) {//如果发送方处于等待ack的状态，作如下处理；否则什么都不做
			//检查校验和是否正确
			int checkSum = pUtils->calculateCheckSum(ackPkt);

			//如果校验和正确，并且确认序号=发送方已发送并等待确认的数据包序号
			if (checkSum == ackPkt.checksum && ackPkt.acknum == this->packetWaitingAck.seqnum) {
				this->expectSequenceNumberSend = 1 - this->expectSequenceNumberSend;			//下一个发送序号在0-1之间切换
				this->waitingState = false;
				pUtils->printPacket("发送方正确收到确认", ackPkt);
				pns->stopTimer(SENDER, this->packetWaitingAck.seqnum);		//关闭定时器
			}
			else {
				pUtils->printPacket("发送方没有正确收到确认，重发上次发送的报文", this->packetWaitingAck);
				pns->stopTimer(SENDER, this->packetWaitingAck.seqnum);									//首先关闭定时器
				pns->startTimer(SENDER, Configuration::TIME_OUT, this->packetWaitingAck.seqnum);			//重新启动发送方定时器
				pns->sendToNetworkLayer(RECEIVER, this->packetWaitingAck);								//重新发送数据包

			}
		}	
	}

	void StopWaitRdtSender::timeoutHandler(int seqNum) {
		//唯一一个定时器,无需考虑seqNum
		pUtils->printPacket("发送方定时器时间到，重发上次发送的报文", this->packetWaitingAck);
		pns->stopTimer(SENDER,seqNum);										//首先关闭定时器
		pns->startTimer(SENDER, Configuration::TIME_OUT,seqNum);			//重新启动发送方定时器
		pns->sendToNetworkLayer(RECEIVER, this->packetWaitingAck);			//重新发送数据包

	}
#endif