3-3：拥塞控制算法

DWORD WINAPI recvhandler(LPVOID lparam)
{
	printwindow();
	int i = (int)(LPVOID)lparam;
	//cout << "接收" << i << endl;
	clock_t finalovertime;
	int t = 0;
	while (base < buffersize)
	{
		if (sendnextseq > base + N || sendnextseq == base)//窗口已满（对方还没有发送ack）或者窗口为空
			Sleep(2);
		message a;
		simplerecv(a);
		if (a.get_ack())//收到确认消息且序号正确
		{
			clockstart = clock();//重置计时器
			if (a.ackseq >= base)//收到正确的消息序号
			{
				if (constatus == 0)
				{
					N += a.ackseq - base + 1;//累积确认
					if (N >= ssthresh)
						constatus = 1;//拥塞避免
					
				}
				else if (constatus == 1)
				{
					N += (a.ackseq - base + 1) / N;//线性增长
				}
				printwindow();
				base = a.ackseq + 1;
				overtime = 0;
				t = 0;
			}
			else if (a.ackseq <= base-1)
			{
				t++;
				cout << t << endl;
				printwindow();
				if (constatus == 2) {//快速恢复
					N += 1;
					if (N >= ssthresh) constatus = 1;//进入拥塞避免阶段
				}
				if (t == 3)//三个冗余ack
				{
					constatus = 2; //快速重传
					overtime = 1;
				}
			}
		}
		clockend = clock();
	}
	cout << "exitpoint2" << endl;
	return 1;
}

DWORD WINAPI sendhandler(LPVOID lparam)//发线程
{
	int flag = 0;
	clock_t s = clock();
	while (base < buffersize)
	{
		int i = (int)(LPVOID)lparam;
		if (!overtime)
		{
			int temp = base;
			if (base + N == sendnextseq)
				Sleep(40);
			for (; sendnextseq < base + N && sendnextseq < buffersize; sendnextseq++)
			{
				flag = 0;//正常发送

				if (!overtime)
				{
					simplesend(msgsend[sendnextseq]);
					s = clock();
					//Sleep(20);
				}

				else {
					break;
				}
				simplesend(msgsend[sendnextseq]);
				if (temp == base)
				{
					clock_t e = clock();
					if ((e - s) / CLOCKS_PER_SEC >= WAIT_TIME)//超时重发
					{
						overtime = 1;
						sendnextseq++;
						break;
					}
				}
			}
		}
		if (overtime == 1)//重新发送
		{
			if (constatus == 1 || constatus == 0)
			{
				ssthresh = N / 2;
				N = 1;
				constatus = 0;//重新进入慢启动阶段
				printwindow();
			}
			else if (constatus == 2)
			{//快速重传
				ssthresh = N / 2;
				N = ssthresh + 3;
			}
			if (flag)
				Sleep(10);//减少重传次数
			for (int i = base; i < sendnextseq; i++)
			{
				//重新发送
				if (overtime)
					simplesend(msgsend[i]); 
				else break;
				flag++;
			}
			overtime = 0;//重传标识归0
			s = clock();//重置计时器
		}
		clock_t e = clock();
		if ((e - s) / CLOCKS_PER_SEC >= WAIT_TIME)//超时重发
			overtime = 1;
	}
	cout << "exitpoint1" << endl;
	return 0;
}