Multicast addresses, if any were configured, would not be good if addrs

  return NULL;

#endif

}

/** Return true iff <b>a</b> is a multicast address.  */

static int

tor_addr_is_multicast(const tor_addr_t *a)

{

  sa_family_t family = tor_addr_family(a);

  if (family == AF_INET) {

    uint32_t ipv4h = tor_addr_to_ipv4h(a);

    if ((ipv4h >> 24) == 0xe0)

      return 1; /* Multicast */

  } else if (family == AF_INET6) {

    const uint8_t *a32 = tor_addr_to_in6_addr8(a);

    if (a32[0] == 0xff)

      return 1;

  }

  return 0;

}

/** Set *<b>addr</b> to the IP address (if any) of whatever interface

 * connects to the Internet.  This address should only be used in checking

 * whether our address has changed.  Return 0 on success, -1 on failure.

    SMARTLIST_FOREACH_BEGIN(addrs, tor_addr_t *, a) {

      if (family != AF_UNSPEC && family != tor_addr_family(a))

        continue;

      if (tor_addr_is_loopback(a))

      if (tor_addr_is_loopback(a) ||

          tor_addr_is_multicast(a))

        continue;

      tor_addr_copy(addr, a);

      rv = 0;