multicastsocket.cpp

组播发送测试网络程序,服务器端

// MulticastSocket.cpp : implementation file
//

#include "stdafx.h"

#include "MulticastSocket.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CMulticastSocket

CMulticastSocket::CMulticastSocket()
{
	bForceNoLoopback = FALSE;
	bDataReceived = TRUE;		/* Variable defined for this project. Not necessarily part of CMulticastSocket */
}

CMulticastSocket::~CMulticastSocket()
{
}


// Do not edit the following lines, which are needed by ClassWizard.
#if 0
BEGIN_MESSAGE_MAP(CMulticastSocket, CAsyncSocket)
	//{{AFX_MSG_MAP(CMulticastSocket)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()
#endif	// 0

/////////////////////////////////////////////////////////////////////////////
// CMulticastSocket member functions

BOOL CMulticastSocket::CreateReceivingSocket(LPCTSTR strGroupIP, UINT nGroupPort)
{
	/* Create socket for receiving packets from multicast group */
	if(!Create(nGroupPort, SOCK_DGRAM, FD_READ))
		return FALSE;

	BOOL bMultipleApps = TRUE;		/* allow reuse of local port if needed */
	SetSockOpt(SO_REUSEADDR, (void*)&bMultipleApps, sizeof(BOOL), SOL_SOCKET);

	/* Fill m_saHostGroup_in for sending datagrams */
	memset(&m_saHostGroup, 0, sizeof(m_saHostGroup));
	m_saHostGroup.sin_family = AF_INET;
	m_saHostGroup.sin_addr.s_addr = inet_addr(strGroupIP);

	if(g_bPortIschanged)
	m_saHostGroup.sin_port = htons(nGroupPort);
     else
		m_saHostGroup.sin_port =  nGroupPort ;	 
	/* Join the multicast group */
 
	m_mrMReq.imr_multiaddr.s_addr = inet_addr(strGroupIP);	
	m_mrMReq.imr_interface.s_addr = htons(INADDR_ANY);		 
    if(g_bIsAddMember){
	 if(setsockopt(m_hSocket, IPPROTO_IP, IP_ADD_MEMBERSHIP,
		 (char FAR *)&m_mrMReq, sizeof(m_mrMReq)) < 0) 
		return FALSE;
//	 AfxMessageBox("multi add member");
    }

 
	return TRUE;
}

BOOL CMulticastSocket::CreateSendingSocket(UINT nTTL, BOOL bLoopBack)
{
	if(!m_SendSocket.Create(0, SOCK_DGRAM, 0))		// Create an unconnected UDP socket
		return FALSE;

	if(!SetTTL(nTTL))								// Set Time to Live as specified by user
		AfxMessageBox("Warning! Error Setting TTL");

	SetLoopBack(bLoopBack);							// Enable/Disable Loopback

	return TRUE;
}

BOOL CMulticastSocket::SetTTL(UINT nTTL)
{
	/* Set Time to Live to parameter TTL */
	if(m_SendSocket.SetSockOpt(IP_MULTICAST_TTL, &nTTL, sizeof(int), IPPROTO_IP) == 0)
		return FALSE;		/* Error Setting TTL */
	else
		return TRUE;		/* else TTL set successfully */
}

void CMulticastSocket::SetLoopBack(BOOL bLoop)
{
	/* Set LOOPBACK option to TRUE OR FALSE according to IsLoop parameter */
	int nLoopBack = (int)bLoop;
	if(m_SendSocket.SetSockOpt(IP_MULTICAST_LOOP, &nLoopBack, sizeof(int),
		IPPROTO_IP) == 0)
	{
		if(!bLoop)						/* if required to stop loopback */
		{
			bForceNoLoopback = TRUE;		/* Internally making a note that loopback has to be disabled forcefilly */

			// Get IP/Port for send socket in order to disable loopback forcefully */
			char localHost[255];
			gethostname(localHost, 255);
			struct hostent *host = gethostbyname(localHost);	/* Get local host IP */
			m_strLocalIP = inet_ntoa (*(struct in_addr*)*host->h_addr_list);
			CString Dummy;			// Dummy string to be passed to the GetSockName function
			m_SendSocket.GetSockName(Dummy, m_nLocalPort);		/* Get Port Number for Sending Port */
		}
	}
}

void CMulticastSocket::OnReceive(int nErrorCode)
{
	int nError = ReceiveFrom (m_strBuffer, 32000, m_strSendersIP, m_nSendersPort);
	if(nError == SOCKET_ERROR)
		AfxMessageBox("Error receiving data from the host group");
	else
	{
		if (!bForceNoLoopback || (bForceNoLoopback && !(m_strSendersIP == m_strLocalIP && m_nSendersPort == m_nLocalPort)))
		{
			// 1. If loopbackback is not to be forced then interface handles the loopback itself
			// 2. If you have to loopback and SOCKOPT LOOPBACK fails, no problem, interfaces loopback by default
			// 3. If you have to stop loopback and SOCKOPT LOOPBACK fails, ignore messages coming from your own sending socket

			// TODO : Add your code for here. The packet received is in m_strBuffer
			bDataReceived = TRUE;	/* Making note that a message has arrived */
		}
	}

	CAsyncSocket::OnReceive(nErrorCode); 
}

BOOL CMulticastSocket::LeaveGroup()
{
	if(setsockopt (m_hSocket, IPPROTO_IP, IP_DROP_MEMBERSHIP, (char FAR *)&m_mrMReq, sizeof(m_mrMReq)) < 0)
		return FALSE;

	m_SendSocket.Close();		// Close sending socket
	Close();					// Close receving socket
	TRACE("close me\n");
	return TRUE;
}

int CMulticastSocket::Send(const void* strMessage, int nSize)
{  int nret=0;
	if((nret=m_SendSocket.SendTo(strMessage, nSize,
		 (SOCKADDR*)&m_saHostGroup, sizeof(SOCKADDR), 0)) == SOCKET_ERROR)
		return SOCKET_ERROR;
	else
		TRACE("ss data=%d\n",nret);
		return nret;
}

BOOL CMulticastSocket::JoinGroup(CString GroupIP, 
								 UINT nGroupPort, 
								 UINT nTTL,
								 BOOL bLoopback)
{
    	if(!CreateReceivingSocket(GroupIP, nGroupPort))		/* Create Socket for receiving and join the host group */
	 		return INVALID_SOCKET;
		if(!CreateSendingSocket(nTTL, bLoopback))			/* Create Socket for sending */
			return INVALID_SOCKET;

		TRACE("join me %s port=%d\n",
			GroupIP,nGroupPort);
		return 1;
}