ipv4_multicast?

static VALUE
addrinfo_ipv4_multicast_p(VALUE self)
{
    uint32_t a;
    if (!extract_in_addr(self, &a)) return Qfalse;
    if ((a & 0xf0000000) == 0xe0000000) /* 224.0.0.0/4 */
        return Qtrue;
    return Qfalse;
}