UDP 통신 (채팅)프로그램 질문입니다.

static UINT UdpServerFunc(LPVOID pVoid)
{
	CServerDlg *dlg = (CServerDlg *)AfxGetApp()->m_pMainWnd;
 
	//------------------------------------------------------
	CString slniPath;
	slniPath.Format(_T("./NetworkPath.ini"));
	TCHAR ServerPort[MAX_PATH];
	int ServerPort_Num;
	GetPrivateProfileString(_T("ServerInfo"), _T("Port"), _T(""), ServerPort, MAX_PATH, slniPath);
	ServerPort_Num = _ttoi(ServerPort);
	//------------------------------------------------------
 
	//Startup Winsock 
	WSADATA wsaData; //WinSock을 위한 내부 자료구조
	int retval = WSAStartup(MAKEWORD(2, 2), &wsaData); 
	if (retval != 0) 
	{
		AfxMessageBox("WSAStartup() Error\n");
		return 0;
	}
 
	//SOCKET
	dlg->server_sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);//IPPROTO_UDP or PPROTO_HOPOPTS
	if (dlg->server_sock == SOCKET_ERROR)
	{
		AfxMessageBox("Socket() Error\n");
		return 0;
	}
 
	//BIND server_addr : socket에 주소를 할당하고 port번호를 할당하기 위함
	ZeroMemory(&dlg->server_addr, sizeof(dlg-> server_addr));
	dlg->server_addr.sin_family = AF_INET;
	dlg->server_addr.sin_port = htons(ServerPort_Num); //30112
	dlg->server_addr.sin_addr.s_addr = htonl(INADDR_ANY); //32bit IPV4 주소
 
	dlg->client_addr.sin_family = AF_INET;
	dlg->client_addr.sin_port = htons(ServerPort_Num);
	dlg->client_addr.sin_addr.s_addr = htonl(INADDR_ANY);
 
	//recvfrom을 받기위해 
	retval = bind(dlg->server_sock, (SOCKADDR*)&dlg->server_addr, sizeof(dlg->server_addr));
 
	AfxMessageBox("server start");
	if (retval == SOCKET_ERROR) {
		AfxMessageBox("bind() ERROR\n");
		return -1;
	}
	//Data Communication
	int addrlength;
	char buf[BUFFER_SIZE];
	int recv_size;
	while (1)
	{		
		//recvfrom()
		addrlength = sizeof(dlg->client_addr);  //데이터를 받을 정보를 같고있는 ---
		recv_size = recvfrom(dlg->server_sock, reinterpret_cast<char*>(buf), BUFFER_SIZE, 0, (SOCKADDR*)&dlg->client_addr, &addrlength);
		if (recv_size == SOCKET_ERROR)
		{
			AfxMessageBox("recvfrom() Error");
			break;
		}
		//Data print
		buf[recv_size] = '\0';
		CString strMsg;
		strMsg = CString(buf, recv_size);
		dlg->m_ListChat.AddString(strMsg);
		strMsg = "";
 
	}
	closesocket(dlg->server_sock);
	WSACleanup;
}

void CServerDlg::OnBnClickedButton2()
{
	CString strText = _T("");
	char Text[BUFFER_SIZE];
	dlg->m_edit_chat.GetWindowText(strText);
	strcpy(Text, strText);
	int send_size = sendto(dlg->server_sock, Text, strlen(Text), 0, (sockaddr*)&dlg->client_addr, sizeof(dlg->client_addr));
	if (send_size == SOCKET_ERROR)
	{
		AfxMessageBox("sendto() Error");
	}
	else
	{
		dlg->m_ListChat.AddString(strText);
	}
 
}

static UINT ClientUdpThreadFunc(LPVOID pVOID) {
 
	CClientTestDlg *dlg = (CClientTestDlg *)AfxGetApp()->m_pMainWnd;
	//----Edit Box에 입력된 정보를 포트/IP 값 가져오기----
	CString slniPath;
	slniPath.Format(_T("./NetworkPath.ini"));
 
	TCHAR ServerPort[MAX_PATH];
	int ServerPort_Num;
	GetPrivateProfileString(_T("ServerInfo"), _T("Port"), _T(""), ServerPort, MAX_PATH, slniPath);
	ServerPort_Num = _ttoi(ServerPort); //30112
 
	TCHAR ServerIp[MAX_PATH];
	int ServerIp_Num;
	GetPrivateProfileString(_T("ServerInfo"), _T("IP"), _T(""), ServerIp, MAX_PATH, slniPath);
	ServerIp_Num = _ttoi(ServerIp); //127.0.0.1
	//--------------------------------------------------
 
 
	//StartUp Winsock
	WSADATA wsaData;
	int retval = WSAStartup(MAKEWORD(2, 2), &wsaData);
	if (retval != 0)
	{
		AfxMessageBox("WSAStartup() Error\n");
		return 0;
	}
 
	//socket
	dlg->clnt_sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP); 
	if (dlg->clnt_sock == SOCKET_ERROR) {
		AfxMessageBox(_T("socket() Error"));
		return 0;
	}
 
	// 소켓 주소 구조체 초기화 (상대 시스템 주소 정보)
	ZeroMemory(&dlg->ServerAddr, sizeof(dlg->ServerAddr));
	dlg->ServerAddr.sin_family = AF_INET; //IP 사용 - IPv4
	dlg->ServerAddr.sin_port = htons(ServerPort_Num); //Port = EditBox에 쓴 값
	dlg->ServerAddr.sin_addr.s_addr = inet_addr(SERVERIP); //SERVERIP = 127.0.0.1
	/*
	dlg->FromServer.sin_family = AF_INET;
	dlg->FromServer.sin_port = htons(ServerPort_Num);
	dlg->FromServer.sin_addr.s_addr = inet_addr(SERVERIP);
	*/
	retval = bind(dlg->clnt_sock, (SOCKADDR*)&dlg->ServerAddr, sizeof(dlg->ServerAddr));
 
	if (retval == SOCKET_ERROR) {
		AfxMessageBox("bind() ERROR\n");
		return -1;
	}
 
	//Data Communication
	CString strMsg;
	int addrlength;
	char buf[BUF_SIZE];
	int recv_size;
 
	while (1) {
		addrlength = sizeof(dlg->FromServer);
		recv_size = recvfrom(dlg->clnt_sock, reinterpret_cast<char*>(buf), BUF_SIZE, 0, (sockaddr*)&dlg->FromServer, &addrlength);
		if (recv_size == SOCKET_ERROR)
		{
			AfxMessageBox("recvfrom() ERROR");
			break;
		}
		else 
		{
			//Data print
			buf[recv_size] = '\0';
			strMsg = CString(buf, recv_size);
			dlg->m_listChat.AddString(strMsg);
			strMsg = "";
		}
 
 
	}		
 
	closesocket(dlg->clnt_sock);
	WSACleanup;
}