tcpserver.cpp File Reference

Server functions over TCP. More...

#include "pch.h"

Macros
#define	WIN32_LEAN_AND_MEAN

Functions
int	CommunicationServerCreateServerAndWaitForClient (PCSTR Port, SOCKET *ClientSocketArg, SOCKET *ListenSocketArg)
	Create server and wait for a client to connect.
int	CommunicationServerReceiveMessage (SOCKET ClientSocket, char *recvbuf, int recvbuflen)
	listen and receive message as the server
int	CommunicationServerSendMessage (SOCKET ClientSocket, const char *sendbuf, int length)
	send message as the server
int	CommunicationServerShutdownAndCleanupConnection (SOCKET ClientSocket, SOCKET ListenSocket)
	Shutdown and cleanup connection as server.

Detailed Description

Server functions over TCP.

Author

Sina Karvandi (sina@.nosp@m.hype.nosp@m.rdbg..nosp@m.org)

Version

0.1

Date

2020-08-21

Copyright

This project is released under the GNU Public License v3.

Macro Definition Documentation

WIN32_LEAN_AND_MEAN

#define WIN32_LEAN_AND_MEAN

Function Documentation

CommunicationServerCreateServerAndWaitForClient()

int CommunicationServerCreateServerAndWaitForClient	(	PCSTR	Port,
		SOCKET *	ClientSocketArg,
		SOCKET *	ListenSocketArg )

Create server and wait for a client to connect.

this function only accepts one client not multiple clients

Parameters

Port
ClientSocketArg
ListenSocketArg

Returns

int

{
    WSADATA wsaData;
    int     iResult;
 
    SOCKET ListenSocket = INVALID_SOCKET;
    SOCKET ClientSocket = INVALID_SOCKET;
 
    struct addrinfo * result = NULL;
    struct addrinfo   hints;
 
    //
    // Initialize Winsock
    //
    iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (iResult != 0)
    {
        ShowMessages("err, WSAStartup failed (%x)\n", iResult);
        return 1;
    }
 
    ZeroMemory(&hints, sizeof(hints));
    hints.ai_family   = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;
    hints.ai_flags    = AI_PASSIVE;
 
    //
    // Resolve the server address and port
    //
    iResult = getaddrinfo(NULL, Port, &hints, &result);
    if (iResult != 0)
    {
        ShowMessages("err, getaddrinfo failed (%x)\n", iResult);
        WSACleanup();
        return 1;
    }
 
    //
    // Create a SOCKET for connecting to server
    //
    ListenSocket =
        socket(result->ai_family, result->ai_socktype, result->ai_protocol);
    if (ListenSocket == INVALID_SOCKET)
    {
        ShowMessages("socket failed with error: %ld\n", WSAGetLastError());
        freeaddrinfo(result);
        WSACleanup();
        return 1;
    }
 
    //
    // Setup the TCP listening socket
    //
    iResult = ::bind(ListenSocket, result->ai_addr, (int)result->ai_addrlen);
    if (iResult == SOCKET_ERROR)
    {
        ShowMessages("err, bind failed (%x)\n", WSAGetLastError());
        freeaddrinfo(result);
        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    }
 
    freeaddrinfo(result);
 
    iResult = listen(ListenSocket, SOMAXCONN);
    if (iResult == SOCKET_ERROR)
    {
        ShowMessages("err, listen failed (%x)\n", WSAGetLastError());
        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    }
 
    //
    // Accept a client socket
    //
    sockaddr_in name    = {0};
    int         addrlen = sizeof(name);
 
    ClientSocket = accept(ListenSocket, (struct sockaddr *)&name, &addrlen);
 
    if (ClientSocket == INVALID_SOCKET)
    {
        ShowMessages("err, accept failed (%x)\n", WSAGetLastError());
        closesocket(ListenSocket);
        WSACleanup();
        return 1;
    }
 
    //
    // Show that we connected to a client
    //
    ShowMessages("connected to : %s:%d\n", inet_ntoa(name.sin_addr), ntohs(name.sin_port));
 
    //
    // Set the argument
    //
    *ClientSocketArg = ClientSocket;
    *ListenSocketArg = ListenSocket;
 
    return 0;
}

CommunicationServerReceiveMessage()

int CommunicationServerReceiveMessage	(	SOCKET	ClientSocket,
		char *	recvbuf,
		int	recvbuflen )

listen and receive message as the server

Parameters

ClientSocket
recvbuf
recvbuflen

Returns

int

{
    int iResult;
 
    //
    // Receive until the peer shuts down the connection
    //
    iResult = recv(ClientSocket, recvbuf, recvbuflen, 0);
    if (iResult > 0)
    {
        //
        // ShowMessages("bytes received: %d\n", iResult);
        //
    }
    else if (iResult == 0)
    {
        //
        // ShowMessages("connection closing...\n");
        //
    }
    else
    {
        ShowMessages("err, recv failed (%x)\n", WSAGetLastError());
        closesocket(ClientSocket);
        WSACleanup();
 
        return 1;
    }
 
    return 0;
}

CommunicationServerSendMessage()

int CommunicationServerSendMessage	(	SOCKET	ClientSocket,
		const char *	sendbuf,
		int	length )

send message as the server

Parameters

ClientSocket
sendbuf
length

Returns

int

{
    int iSendResult;
 
    //
    // Echo the buffer back to the sender
    //
    iSendResult = send(ClientSocket, sendbuf, length, 0);
    if (iSendResult == SOCKET_ERROR)
    {
        /*
    ShowMessages("err, send failed (%x)\n", WSAGetLastError());
    closesocket(ClientSocket);
    WSACleanup();
        */
        return 1;
    }
    return 0;
}

CommunicationServerShutdownAndCleanupConnection()

int CommunicationServerShutdownAndCleanupConnection	(	SOCKET	ClientSocket,
		SOCKET	ListenSocket )

Shutdown and cleanup connection as server.

Parameters

ClientSocket
ListenSocket

Returns

int

{
    int iResult;
 
    //
    // No longer need server socket
    //
    closesocket(ListenSocket);
 
    //
    // shutdown the connection since we're done
    //
    iResult = shutdown(ClientSocket, SD_SEND);
    if (iResult == SOCKET_ERROR)
    {
        //
        // We comment this line because the connection might be removed;
        // thus, we don't need to show error
        //
 
        /*
    ShowMessages("err, shutdown failed (%x)\n", WSAGetLastError());
    */
 
        closesocket(ClientSocket);
        WSACleanup();
        return 1;
    }
 
    //
    // cleanup
    //
    closesocket(ClientSocket);
    WSACleanup();
 
    return 0;
}