shagil / netwo

This project/software for those who want to understand the working of TCP (Transmission Control Protocol), also the understanding of how connection establishment occur and how the message send through that.

netwo

This project/software for those who want to understand the working of TCP (Transmission Control Protocol) also the understanding of how connection establishment occur and how the message send through that.

Server side code: // Need to link with Ws2_32.lib #pragma comment (lib, "Ws2_32.lib") // #pragma comment (lib, "Mswsock.lib")

#define DEFAULT_BUFLEN 512 #define DEFAULT_PORT "27015" using namespace std;

int __cdecl main(void) { WSADATA wsaData; int iResult;

SOCKET ListenSocket = INVALID_SOCKET;
SOCKET ClientSocket = INVALID_SOCKET;

struct addrinfo *result = NULL;
struct addrinfo hints;

int iSendResult;
char recvbuf[DEFAULT_BUFLEN];
int recvbuflen = DEFAULT_BUFLEN;
cout<<"TCP connection established ...ready to accept packet";
// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != 0) {
    printf("WSAStartup failed with error: %d\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, DEFAULT_PORT, &hints, &result);
if ( iResult != 0 ) {
    printf("getaddrinfo failed with error: %d\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) {
    printf("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) {
    printf("bind failed with error: %d\n", WSAGetLastError());
    freeaddrinfo(result);
    closesocket(ListenSocket);
    WSACleanup();
    return 1;
}

freeaddrinfo(result);

iResult = listen(ListenSocket, SOMAXCONN);
if (iResult == SOCKET_ERROR) {
    printf("listen failed with error: %d\n", WSAGetLastError());
    closesocket(ListenSocket);
    WSACleanup();
    return 1;
}

// Accept a client socket
ClientSocket = accept(ListenSocket, NULL, NULL);
if (ClientSocket == INVALID_SOCKET) {
    printf("accept failed with error: %d\n", WSAGetLastError());
    closesocket(ListenSocket);
    WSACleanup();
    return 1;
}

// No longer need server socket
closesocket(ListenSocket);

// Receive until the peer shuts down the connection
do {

    iResult = recv(ClientSocket, recvbuf, recvbuflen, 0);
    if (iResult > 0) {
        printf("Bytes received: %d\n", iResult);
		recvbuf[iResult]='\0';
    // Echo the buffer back to the sender
		cout<<recvbuf<<endl;
        iSendResult = send( ClientSocket, recvbuf, iResult, 0 );
        if (iSendResult == SOCKET_ERROR) {
            printf("send failed with error: %d\n", WSAGetLastError());
            closesocket(ClientSocket);
            WSACleanup();
            return 1;
        }
        printf("Bytes sent: %d\n", iSendResult);
    }
    else if (iResult == 0)
        printf("Connection closing...\n");
    else  {
        printf("recv failed with error: %d\n", WSAGetLastError());
        closesocket(ClientSocket);
        WSACleanup();
        return 1;
    }

} while (iResult > 0);

// shutdown the connection since we're done
iResult = shutdown(ClientSocket, SD_SEND);
if (iResult == SOCKET_ERROR) {
    printf("shutdown failed with error: %d\n", WSAGetLastError());
    closesocket(ClientSocket);
    WSACleanup();
    return 1;
}

// cleanup
closesocket(ClientSocket);
WSACleanup();

return 0;

}

---

Client side code: #include "stdafx.h" #define WIN32_LEAN_AND_MEAN #include #include <windows.h> #include <winsock2.h> #include <ws2tcpip.h> #include <stdlib.h> #include <stdio.h> using namespace std;

// Need to link with Ws2_32.lib, Mswsock.lib, and Advapi32.lib #pragma comment (lib, "Ws2_32.lib") #pragma comment (lib, "Mswsock.lib") #pragma comment (lib, "AdvApi32.lib")

#define DEFAULT_BUFLEN 512 #define DEFAULT_PORT "27015"

int __cdecl main(int argc, char **argv) { WSADATA wsaData; SOCKET ConnectSocket = INVALID_SOCKET; struct addrinfo *result = NULL, *ptr = NULL, hints; // char *sendbuf = "this is a test"; char *sendbuf; char recvbuf[DEFAULT_BUFLEN]; int iResult; int recvbuflen = DEFAULT_BUFLEN;

// Validate the parameters
if (argc != 2) {
    printf("usage: %s server-name\n", argv[0]);
    return 1;
}

// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2,2), &wsaData);
if (iResult != 0) {
    printf("WSAStartup failed with error: %d\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(argv[1], DEFAULT_PORT, &hints, &result);
if ( iResult != 0 ) {
    printf("getaddrinfo failed with error: %d\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) {
        printf("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) {
    printf("Unable to connect to server!\n");
    WSACleanup();
    return 1;
}

do{// Send an initial buffer
printf("Enter the msg to send : ");
scanf("%s",sendbuf);
iResult = send( ConnectSocket, sendbuf, (int)strlen(sendbuf), 0 );
if (iResult == SOCKET_ERROR) {
    printf("send failed with error: %d\n", WSAGetLastError());
    closesocket(ConnectSocket);
    WSACleanup();
    return 1;
}

}while(1);

printf("Bytes Sent: %ld\n", iResult);

// shutdown the connection since no more data will be sent
iResult = shutdown(ConnectSocket, SD_SEND);
if (iResult == SOCKET_ERROR) {
    printf("shutdown failed with error: %d\n", WSAGetLastError());
    closesocket(ConnectSocket);
    WSACleanup();
    return 1;
}

// Receive until the peer closes the connection
do {

    iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
    if ( iResult > 0 )
        printf("Bytes received: %d\n", iResult);
    else if ( iResult == 0 )
        printf("Connection closed\n");
    else
        printf("recv failed with error: %d\n", WSAGetLastError());

} while( iResult > 0 );

// cleanup
closesocket(ConnectSocket);
WSACleanup();

return 0;

}