setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));
setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &val, sizeof(val));
setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
setsockopt(sock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &val, sizeof(val));