UDP winsock chat program receives -1 from recvfrom() and sendto() - c

Question

Currently, we are producing UDP chat programs using MFC and C.
I'm working on both bind because I have to send incoming messages from the server and client.
An error occurs when recvfrom() and sendto(), they return -1.
I don't know what the problem is. I searched it and did what I did, but it's not working.
Why does sendto() and recvfrom() return -1?
I don't know what the problem is.
server Code
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;
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;
}
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);
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);
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);
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;
}
Server Sendto Code
void CServerDlg::OnBnClickedButton2()
{
CServerDlg *dlg = (CServerDlg *)AfxGetApp()->m_pMainWnd;
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);
}
}
Client Code
static UINT ClientUdpThreadFunc(LPVOID pVOID) {
CClientTestDlg *dlg = (CClientTestDlg *)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); //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;
}
ZeroMemory(&dlg->ServerAddr, sizeof(dlg->ServerAddr));
dlg->ServerAddr.sin_family = AF_INET;
dlg->ServerAddr.sin_port = htons(ServerPort_Num);
dlg->ServerAddr.sin_addr.s_addr = inet_addr(SERVERIP);
/*
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;
}
Client Sendto Code
void CClientTestDlg::OnBnClickedButtonSend()
{
CClientTestDlg *dlg = (CClientTestDlg *)AfxGetApp()->m_pMainWnd;
CString UdpStrText = _T("");
char Text[BUF_SIZE];
m_editChat.GetWindowText(UdpStrText);
strcpy(Text, UdpStrText);
int UdpRtn;
UdpRtn = sendto(dlg->clnt_sock, Text, strlen(Text), 0, (SOCKADDR*)&dlg->ServerAddr, sizeof(dlg->ServerAddr));
if (UdpRtn == SOCKET_ERROR)
{
AfxMessageBox("sendto() ERROR\n %s");
}
closesocket(dlg->clnt_sock);
}