Help with Multicast and bind problem needed

  • Thread starter Thread starter Ron Hall
  • Start date Start date
R

Ron Hall

I have an application that uses multicast and I'm trying to extend it to
support machines multiple adapters allowing the user to select the adapter
to use. I added a bind statement to the socket initialization and now
communications no longer work. So I'm clearly doing something wrong or not
understanding something. I've included a brief snippet of code that I'm
trying to get working, if someone can point me at my problem I would greatly
appreciate it.

m_rcvsock = WSASocket(AF_INET, SOCK_DGRAM, 0, NULL, 0,
WSA_FLAG_MULTIPOINT_C_LEAF | WSA_FLAG_MULTIPOINT_D_LEAF);
assert(m_rcvsock != INVALID_SOCKET);
nOptVal = 0;
irtn = WSAIoctl(m_rcvsock, SIO_MULTIPOINT_LOOPBACK, &nOptVal,
sizeof(nOptVal),
NULL, 0, (PULONG) &irtn, NULL, NULL);
assert(irtn == 0);
nOptVal = 1;
irtn = WSAIoctl(m_rcvsock, SIO_MULTICAST_SCOPE, &nOptVal,
sizeof(nOptVal),
NULL, 0, (PULONG) &irtn, NULL, NULL);
assert(irtn == 0);

// bind to the specified adapter

sa.sin_family = AF_INET;
sa.sin_addr.S_un.S_addr = ulAdapter;
sa.sin_port = 0;
irtn = bind(m_rcvsock, (sockaddr *) &sa, sizeof(sockaddr_in));
assert(irtn == 0);

// now join this socket as a leaf in the multicast group

WSAEventSelect(m_rcvsock, m_EventHandle, FD_CONNECT);
WSAResetEvent(m_EventHandle);
sa.sin_family = AF_INET;
sa.sin_addr.s_addr = htonl(ulRcvIP);
sa.sin_port = htons(usRcvPort);
irtn = WSAJoinLeaf(m_rcvsock, (sockaddr *) &sa, sizeof(sa),
NULL, NULL, NULL, NULL, JL_RECEIVER_ONLY);
assert(irtn == m_rcvsock);
irtn = WaitForSingleObject(m_EventHandle, 1000);
if (irtn != WAIT_OBJECT_0)
return IDS_NO_CONNECT;

If I comment out the bind statement and the assert that follows
communication works just fine.

TIA
Ron
 
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