main.cpp

// Coded by Kirisan Manivannan
// Credit to: Sloan Kelley; https://www.youtube.com/watch?v=WDn-htpBlnU
// TCP-Server

#include <iostream>
#include <WS2tcpip.h>
#pragma comment(lib, "ws2_32.lib")

using namespace std;

void main() {

	// Initialze winsock
	WSADATA wsData;
	WORD ver = MAKEWORD(2, 2);

	int wsOk = WSAStartup(ver, &wsData);
	if (wsOk != 0) {
		cerr << "Can't Initialize winsock! Quitting" << endl;
		return;
	}

	// Create a socket
	SOCKET listening = socket(AF_INET, SOCK_STREAM, 0);
	if (listening == INVALID_SOCKET) {
		cerr << "Can't create a socket! Quitting" << endl;
		return;
	}

	// Bind the IP address and port to a socket
	sockaddr_in hint;
	hint.sin_family = AF_INET;
	hint.sin_port = htons(54000);					// htons = host to network short
	hint.sin_addr.S_un.S_addr = INADDR_ANY;			// Could also use inet_pton...

	bind(listening, (sockaddr*)&hint, sizeof(hint));

	// Tell winsock the socket is for listening
	listen(listening, SOMAXCONN);

	// Wait for a connection
	sockaddr_in client;
	int clientSize = sizeof(client);

	SOCKET clientSocket = accept(listening, (sockaddr*)&client, &clientSize);
	
	char host[NI_MAXHOST];							// Client's remote name
	char service[NI_MAXHOST];						// Service (i.e port) the client is connect on

	ZeroMemory(host, NI_MAXHOST);
	ZeroMemory(service, NI_MAXHOST);

	if (getnameinfo((sockaddr*)&client, sizeof(client), host, NI_MAXHOST, service, NI_MAXSERV, 0) == 0) {
		cout << host << " Connected on port " << service << endl;
	}
	else {
		inet_ntop(AF_INET, &client.sin_addr, host, NI_MAXHOST);
		cout << host << " Connected on port " << 
			ntohs(client.sin_port) << endl;			// ntohs = 	network to host short
	}

	// Close listening socket
	closesocket(listening);

	// While loop: accept and echo message back to client
	char buf[4096];

	while (true) {
		ZeroMemory(buf, 4096);

		// Wait for client to send data
		int bytesReceived = recv(clientSocket, buf, 4096, 0);
		if (bytesReceived == SOCKET_ERROR) {
			cerr << "Error in recv(). Quitting" << endl;
			break;
		}
		
		if (bytesReceived == 0) {
			cout << "Client disconnected " << endl;
			break;
		}

		// Echo message back to client
		send(clientSocket, buf, bytesReceived + 1, 0);
	}

	// Close the sock
	closesocket(clientSocket);

	// Cleanup winsock
	WSACleanup();
}