[Opensim-dev] DNS lookup and caching

[Justin Clark-Casey]

The 6-8 week estimate was based on a quick plunge through the code to give an estimate to the client I had at the time. 
  I didn't do any actual work so unfortunately I have no detailed design and I can't guarantee this would work.

My initial thought was to have some syntax in the ExternalHostName field that could allow two addresses and specify when 
each would be used.  For example, perhaps

ExternalHostName = 192.168.1.2:192.168.1.0/24;63.3.19.155

to specify that all requests originating from the 192.168.1.0/24 subnet would be served the local IP 192.168.1.2 but all 
others would receive 63.3.19.155.  One requirement for any scheme is that it is backward compatible (i.e. just a single 
IP address/FQDN will behave as it does now).

This then needs to flow throughout OpenSimulator so that at the crucial UDP points (login/entity transfer) one will 
serve back the correct address in response to a client request.  I expect this data will have to be stored in the 
Regions db table which might require an expansion of the current varchar(64) type for serverIP.

Trying to match this to all the HTTP parts where an address is separately specified would be a massive pain but 
hopefully is completely unnecessary, as one can give FQDNs at those points which are resolved dynamically (I think!).

The usual practice for code submission is to create a patch and then put it on the Mantis database in "Patch Included" 
state, as described at [1].  It is then assessed by a core developer(s) and included or feedback given as appropriate. 
In this case, though, I would also like to see some feature proposal doc [2] before a patch, if only to see what the 
proposed config format is and catch any early problems.  Also, this is the kind of significant feature where I think we 
would want to have see a contribution agreement, which core and other developers have done.  More details at [3].

I'm very happy to keep discussing this on this list.  A proposal or even a patch doesn't need to be complete before it's 
public.  In fact, I'd much prefer to discuss issues as they come up so that myself and other people on this list can 
identify problems early and even point out if there are basic issues with the idea of serving different IP addresses for 
UDP to different clients based on their requesting IP.

[1] http://opensimulator.org/wiki/Submitting_code_to_OpenSim
[2] http://opensimulator.org/wiki/Feature_Proposals
[3] http://opensimulator.org/wiki/Contributions_Policy



On 18/12/14 14:07, Michael Heilmann wrote:
> Justin
>
> The inability to pass a FQDN to the client is interesting, I did not see that.
>
> Doug and I discussed our level of interest in this functionality, and your solution.  I will begin work to explore and
> implement your solution immediately.  As I am not a core developer, and in fact this would be my first contribution to
> opensim, I may need some guidance on your normal code submission practices.  We (MOSES) have our own git clone of
> opensim master on github that I will be working out of.
>


-- 
Justin Clark-Casey (justincc)
OSVW Consulting
http://justincc.org
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