tcpclient.cpp File Reference

Server functions over TCP. More...

#include "pch.h"

Functions
INT	CommunicationClientConnectToServer (PCSTR Ip, PCSTR Port, SOCKET *ConnectSocketArg)
	communication for client, connecting to the server
INT	CommunicationClientSendMessage (SOCKET ConnectSocket, const CHAR *sendbuf, INT buflen)
	Send message a client.
INT	CommunicationClientShutdownConnection (SOCKET ConnectSocket)
	shutdown the connection as a client
INT	CommunicationClientReceiveMessage (SOCKET ConnectSocket, CHAR *RecvBuf, UINT32 MaxBuffLen, PUINT32 BuffLenRecvd)
	Receive message as a client.
INT	CommunicationClientCleanup (SOCKET ConnectSocket)
	cleanup the connection as client

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.

Function Documentation

CommunicationClientCleanup()

INT CommunicationClientCleanup

(

SOCKET

ConnectSocket

)

cleanup the connection as client

Parameters

ConnectSocket

Returns

INT

{
    //
    // cleanup
    //
    closesocket(ConnectSocket);
    WSACleanup();
 
    return 0;
}

CommunicationClientConnectToServer()

INT CommunicationClientConnectToServer	(	PCSTR	Ip,
		PCSTR	Port,
		SOCKET *	ConnectSocketArg )

communication for client, connecting to the server

Parameters

Ip
Port
ConnectSocketArg

Returns

INT

{
    WSADATA          wsaData;
    SOCKET           ConnectSocket = INVALID_SOCKET;
    struct addrinfo *result = NULL, *ptr = NULL, hints;
    INT              IResult;
 
    //
    // 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_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;
 
    //
    // Resolve the server address and port
    //
    IResult = getaddrinfo(Ip, Port, &hints, &result);
    if (IResult != 0)
    {
        ShowMessages("getaddrinfo failed (%x)\n", IResult);
        WSACleanup();
        return 1;
    }
 
    //
    // Attempt to connect to an address until one succeeds
    //
    for (ptr = result; ptr != NULL; ptr = ptr->ai_next)
    {
        //
        // Create a SOCKET for connecting to server
        //
        ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype, ptr->ai_protocol);
        if (ConnectSocket == INVALID_SOCKET)
        {
            ShowMessages("socket failed with error: %ld\n", WSAGetLastError());
            WSACleanup();
            return 1;
        }
 
        //
        // Connect to server.
        //
        IResult = connect(ConnectSocket, ptr->ai_addr, (INT)ptr->ai_addrlen);
        if (IResult == SOCKET_ERROR)
        {
            closesocket(ConnectSocket);
            ConnectSocket = INVALID_SOCKET;
            continue;
        }
        break;
    }
 
    freeaddrinfo(result);
 
    if (ConnectSocket == INVALID_SOCKET)
    {
        ShowMessages("unable to connect to the server\n");
        WSACleanup();
        return 1;
    }
 
    //
    // Store the arguments
    //
    *ConnectSocketArg = ConnectSocket;
 
    return 0;
}

CommunicationClientReceiveMessage()

INT CommunicationClientReceiveMessage	(	SOCKET	ConnectSocket,
		CHAR *	RecvBuf,
		UINT32	MaxBuffLen,
		PUINT32	BuffLenRecvd )

Receive message as a client.

Parameters

ConnectSocket
RecvBuf
MaxBuffLen
BuffLenRecvd

Returns

INT

{
    INT Result;
 
    //
    // Receive until the peer closes the connection
    //
    Result = recv(ConnectSocket, RecvBuf, MaxBuffLen, 0);
    if (Result > 0)
    {
        //
        // Set recvd buff len
        //
        *BuffLenRecvd = Result;
 
        /*
    ShowMessages("bytes received: %d\n", iResult);
        */
    }
    else if (Result == 0)
    {
        //
        // Last packet
        //
    }
    else
    {
        ShowMessages("\nrecv failed with error: %d\n", WSAGetLastError());
        ShowMessages("the remote system closes the connection.\n\n");
 
        return 1;
    }
 
    return 0;
}

CommunicationClientSendMessage()

INT CommunicationClientSendMessage	(	SOCKET	ConnectSocket,
		const CHAR *	sendbuf,
		INT	buflen )

Send message a client.

Parameters

ConnectSocket
sendbuf
buflen

Returns

INT

{
    INT IResult;
 
    //
    // Send an initial buffer
    //
    IResult = send(ConnectSocket, sendbuf, buflen, 0);
    if (IResult == SOCKET_ERROR)
    {
        ShowMessages("err, send failed (%x)\n", WSAGetLastError());
        closesocket(ConnectSocket);
        WSACleanup();
        return 1;
    }
 
    return 0;
}

CommunicationClientShutdownConnection()

INT CommunicationClientShutdownConnection

(

SOCKET

ConnectSocket

)

shutdown the connection as a client

Parameters

ConnectSocket

Returns

INT

{
    INT IResult;
 
    //
    // shutdown the connection since no more data will be sent
    //
    IResult = shutdown(ConnectSocket, 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(ConnectSocket);
        WSACleanup();
        return 1;
    }
    return 0;
}