IPv6 Multicasting (2) examples

Sending multicast packets

s = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);  /* XXX use getaddrinfo instead */

/* specify the outgoing interface */
ifindex = if_nametoindex(outifname);  /* e.g. outifname = "ne0" */
setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_IF,
        &ifindex, sizeof(ifindex));

/* specify the hoplimit: note that the system default is 1 */
hlim = 64;
setsockopt(s, IPPROTO_IPV6, IPV6_MULTICAST_HOPS,
        &hlim, sizeof(hlim));

/* send a packet */
sendto(s, buf, buflen, 0, dst, dstlen);