Multicast example for WSA

mcast.cpp

#include "stdafx.h"

#include "resolve.h"
#include <WinSock2.h>
#include <WS2tcpip.h>
#include <MSWSock.h>

#pragma comment (lib, "Ws2_32.lib")


#define MAX_LEN 256

struct MyApp
{

	struct
	{
		int argc;
		char** argv;
	} m_args;

	SOCKET m_socketFd;
	int m_sockOptFlag;
	struct sockaddr_in m_macaddr;
	
	struct
	{
		char data[MAX_LEN + 1];
		int len;
	} m_recvString;

	struct ip_mreq m_req;
	char m_mcaddr_str[64];
	unsigned int m_port;
	struct sockaddr_in m_fromAddress;
	 int m_fromLen;
	WSADATA m_wsa;

public:
	explicit MyApp(int argc, char** argv)
		: m_args({argc, argv})
	{
		memset(m_mcaddr_str, 0, sizeof(m_mcaddr_str));
		strcat_s(m_mcaddr_str, "224.1.50.15");
		m_port = 1234;
	}

	~MyApp() 
	{
		if ((setsockopt(m_socketFd, IPPROTO_IP, IP_DROP_MEMBERSHIP,
			(char*)&m_req, sizeof(m_req))) < 0)
		{
			perror("setsockopt() failed");
		}

		closesocket(m_socketFd);
		WSACleanup();
	}

	bool init()
	{
		bool res = false;
		if (WSAStartup(MAKEWORD(2, 0), &m_wsa) != 0)
		{
			fprintf(stderr, "Failed to load WSA\n");
			return res;
		}

		if ( (m_socketFd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
		{
			perror("socket() failed");
			printf("Last error (%d)\n" , WSAGetLastError());
			return res;
		}

		if ((setsockopt(m_socketFd, SOL_SOCKET, SO_REUSEADDR, (char*)&m_sockOptFlag,
			sizeof(m_sockOptFlag)) ) < 0)
		{
			perror("setsockopt() failed");
			return res;
		}

		memset(&m_macaddr, 0, sizeof(m_macaddr));
		m_macaddr.sin_family = AF_INET;
		m_macaddr.sin_addr.S_un.S_addr = htonl(INADDR_ANY);
		m_macaddr.sin_port = htons(m_port);

		{
			res = true;
		}
		return res;
	}

	bool bind()
	{
		bool res = false;

		if (::bind(m_socketFd, (struct sockaddr*) &m_macaddr, sizeof(m_macaddr)) < 0)
		{
			perror("bind() failed");
			return res;
		}

		if (inet_pton(AF_INET, m_mcaddr_str, &m_req.imr_multiaddr.S_un.S_addr) <=0)
		{
			perror("inet_pton() failed with error");
			return res;
		}
		m_req.imr_interface.S_un.S_addr = htonl(INADDR_ANY);

		if (setsockopt(m_socketFd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char*)&m_req, sizeof(m_req)) < 0)
		{
			perror("setsockopt() failed");
			printf("Last error(%d)\n", WSAGetLastError());
			return res;
		}

		int recv_len = 0;
		res = true;

		for (;;)
		{
			memset(m_recvString.data, 0, sizeof(m_recvString));
			m_fromLen = sizeof(m_fromAddress);
			memset(&m_fromAddress, 0, m_fromLen);

			if ((recv_len = recvfrom(m_socketFd, m_recvString.data, MAX_LEN, 0,
				(struct sockaddr*)&m_fromAddress, &m_fromLen)) < 0)
			{
				perror("recvfrom() failed");
				res = false;
				break;
			}

			printf("Received %d bytes\n");
			printf("%s\n", m_recvString.data);
			
		}

		return res;
	}



};

int __cdecl main(int argc, char** argv)
{
	MyApp app(argc, argv);
	if (app.init())
		app.bind();

	return 0;
}