[ECOS] Receiving Multicast Packets on a socket

Adolfo Lucha Adolfo.Lucha@controlware.de
Wed Sep 10 07:10:00 GMT 2003


Hello,

I tried to receive Packets sent by routers to the multicast address 224.0.0.2. I coded:

...cat...

    int one = 1;
    
    s = socket(AF_INET, SOCK_DGRAM, 0);

    if (s < 0)
    {
    	printf("datagram socket failed");
    	return -1;
    }
    
    if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, &one, sizeof(one)))
    {
    	printf("setsockopt SO_BROADCAST error");
    	return -1;
    }
    
    memset(&local, 0, sizeof(local));
    local.sin_family = AF_INET;
    local.sin_len    = sizeof(local);
    local.sin_port   = htons(HSRP_PORT_NUMBER);
    local.sin_addr.s_addr = inet_addr("224.0.0.2"); // or INADDR_ANY ?
    
    if(bind(s, (struct sockaddr *) &local, sizeof(local)) < 0)
    {
    	printf("bind error");
    	return -1;
    }

    ret = recvfrom(s, &HsrpPacket, sizeof(HsrpPacket), (int)0,\
                             (struct sockaddr *)&client_addr, (socklen_t *)&client_addr_len);

...cat...

But recvfrom() never returns. What am I doing wrong? Hints are appreciated.

Regards
Adolfo



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