On Fri, Oct 29, 2010 at 12:07:30AM +0300, Julian Anastasov wrote: > > Hello, > > On Thu, 28 Oct 2010, Simon Horman wrote: > > >As it stands a little more than 256 bytes may be needed for > >pe_data (+ pe_name_length + pe_name). This could be resolved by > >shortening the maximum pe_data length. Or perhaps we could use 16 bytes for > >Option length, which should ensure its never too small. > > > >The 256 byte limit that I made for pe_data was arbitrarily chosen. > > Yes, this is a problem. > > >>>We can have a better fine tuning of options in this way. > >> > >> Yes, that is exactly my idea. I more like the name > >>"Parameter" instead of "Option", i.e. we have additional > >>parameters that can be mandatory (usually) but also can be > >>optional. For now I don't have idea for any optional > >>parameters but allocating 1 bit for this does not look > >>fatal. > > > >I'm not sure I understand the motivation for optional parameters. > >I think its important to allow for backwards compatibility. But > >I don't see that there will be multiple independent implementations > >of the synchronisation daemon in the near future. So the use-case > >isn't clear to me. > > If we want to support optional parameters they > must have some known length field, 16 bits if needed. At this point I see no strong reason to support optional parameters. > But if we don't want such optional parameters then > we can just use single octet for parameter type > which can imply the length of the following data. Types that have > data with variable length should provide > 1 or 2 octets after the parameter type for their length. > > So, the parsing should be per-type. If one day > we need optional parameters we can just add 1 octet for > type and 2 for length before data. > > For example, ip_vs_sync_conn_options if implemented > as parameter can be coded with 1 octet for type and the > following data structure. OTOH, PE params can use 1 octet > for type, 2 for length (read with get_unaligned_be16) and > then data. Agreed. With such a scheme it would be possible to have pe_data and pe_name as a single type - but two types is also fine by me. -- To unsubscribe from this list: send the line "unsubscribe lvs-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
