compare_buffered_updates(const void *av, const void *bv)
{
    const struct buffered_update *a = av, *b = bv;
    int rc, v4a, v4b, ma, mb;

    rc = memcmp(a->id, b->id, 8);
    if(rc != 0)
        return rc;

    v4a = (a->plen >= 96 && v4mapped(a->prefix));
    v4b = (b->plen >= 96 && v4mapped(b->prefix));

    if(v4a > v4b)
        return 1;
    else if(v4a < v4b)
        return -1;

    ma = (!v4a && a->plen == 128 && memcmp(a->prefix + 8, a->id, 8) == 0);
    mb = (!v4b && b->plen == 128 && memcmp(b->prefix + 8, b->id, 8) == 0);

    if(ma > mb)
        return -1;
    else if(mb > ma)
        return 1;

    if(a->plen < b->plen)
        return 1;
    else if(a->plen > b->plen)
        return -1;

    return memcmp(a->prefix, b->prefix, 16);
}
compare_buffered_updates(const void *av, const void *bv)
{
    const struct buffered_update *a = av, *b = bv;
    int rc, v4a, v4b, ma, mb;

    rc = memcmp(a->id, b->id, 8);
    if(rc != 0)
        return rc;

    v4a = (a->plen >= 96 && v4mapped(a->prefix));
    v4b = (b->plen >= 96 && v4mapped(b->prefix));

    if(v4a > v4b)
        return 1;
    else if(v4a < v4b)
        return -1;

    ma = (!v4a && a->plen == 128 && memcmp(a->prefix + 8, a->id, 8) == 0);
    mb = (!v4b && b->plen == 128 && memcmp(b->prefix + 8, b->id, 8) == 0);

    if(ma > mb)
        return -1;
    else if(mb > ma)
        return 1;

    if(a->plen < b->plen)
        return 1;
    else if(a->plen > b->plen)
        return -1;

    return memcmp(a->prefix, b->prefix, 16);
}