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188 lines
5.3 KiB
C++

// MulticastSocket.cpp : implementation file
//
#include "stdafx.h"
#include "MulticastSocket.h"
#include "Mmc.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
/////////////////////////////////////////////////////////////////////////////
// CMulticastSocket
CMulticastSocket::CMulticastSocket()
{
m_RevData = NULL;
m_nSendersPort = 0;
m_nLocalPort = 0;
bForceNoLoopback = FALSE;
if (!AfxSocketInit())
{
//MessageBox(NULL,_T("Failed to Initialize Sockets"),"ͼÏñÏÔʾ", MB_OK | MB_ICONSTOP);
MessageBoxEx(NULL,"Failed to Initialize Sockets","ImageShow",MB_OK|MB_ICONSTOP,MAKELANGID(LANG_ENGLISH,SUBLANG_ENGLISH_US));
}
}
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);
m_saHostGroup.sin_port = htons((USHORT)nGroupPort);
/* Join the multicast group */
m_mrMReq.imr_multiaddr.s_addr = inet_addr(strGroupIP); /* group addr */
m_mrMReq.imr_interface.s_addr = htons(INADDR_ANY); /* use default */
if(setsockopt(m_hSocket, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char FAR *)&m_mrMReq, sizeof(m_mrMReq)) < 0)
{
int nn = WSAGetLastError();
return FALSE;
}
BOOL bOptVal = 1;
if (setsockopt(m_hSocket, IPPROTO_UDP, 1, (char*)&bOptVal, sizeof(bOptVal)) <0)
{
printf("Set UDP_NOCHECKSUM: TRUE\n");
return FALSE;
}
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
MessageBoxEx(NULL,"Warning! Error Setting TTL","ImageShow",NULL,MAKELANGID(LANG_ENGLISH,SUBLANG_ENGLISH_US));
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, 10240, m_strSendersIP, m_nSendersPort);
if(nError == SOCKET_ERROR)
{
MessageBoxEx(NULL,"Error receiving data from the host group","ImageShow",NULL,MAKELANGID(LANG_ENGLISH,SUBLANG_ENGLISH_US));
}
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
if ( m_RevData != NULL)
{
m_RevData( m_strBuffer, nError);
}
}
}
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();
return TRUE;
}
BOOL CMulticastSocket::SendTo(const void* strMessage, int nSize)
{
if(m_SendSocket.SendTo(strMessage, nSize, (SOCKADDR*)&m_saHostGroup, sizeof(SOCKADDR), 0) == SOCKET_ERROR)
{
return FALSE;
}
else
{
return TRUE;
}
}
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 FALSE;
}
if(!CreateSendingSocket(nTTL, bLoopback)) /* Create Socket for sending */
{
return FALSE;
}
return TRUE;
}