[Commotion-dev] DNS Update

[Will Hawkins]

Hey Hans,

Just wondering if you had a chance to consider these patches?

On 05/16/2012 01:01 PM, Will Hawkins wrote:
> I uploaded a set of patches to redmine that should implement this.
> Please take a look at your convenience and provide feedback. I am eager
> to hear what you think.
> 
> To get the new feature, follow the instructions in the README (basically
> update android.env and run ./build_external.sh).
> 
> As an overview, here's how the new dns setup works:
> 
> On connection to the mesh,
> 1. the user's DNS server preference is taken from the preferences and
> stashed in app_bin/resolv.conf
> 2. The system-wide dns server is set to 127.0.0.1
> 3. adsuck (the name of the dns server binary) is launched. Its pid is
> stored in the app_bin/adsuck.pid file.
> 4. olsrd is started with a properly configured nameservice plug-in.
> At this point, adsuck is now ready to do .mesh -> address translations.
> 
> When olsrd receives an updated DNS entry,
> 1. The mapping is automatically reflected in
> app_bin/chroot/hosts.android.small.
> 2. The adsuck process (whose pid is found in app_bin/adsuck.pid) is
> signalled with HUP to indicate that there were changes to its data source.
> 3. adsuck rereads app_bin/chroot/hosts.android.small.
> 
> On disconnection from the mesh,
> 1. The application resets the system-wide dns server to what it was
> before connecting.
> 
> Please let me know if this makes sense. I am eager to get feedback on
> the approach and how it works. It's pretty cool to be able to go to
> http://commotion-xxxx.mesh from the Android browser.
> 
> Will
> 
> 
> On 05/15/2012 03:30 PM, Will Hawkins wrote:
>> You can now find discussion of this item on Redmine in the
>> commotion-android project under Feature #300.
>>
>> https://code.commotionwireless.net/issues/300
>>
>> Will
>>
>> On 05/15/2012 01:25 PM, Will Hawkins wrote:
>>> Thanks for this Hans.
>>>
>>> This setup is meant now only for Android, but it could be useful for
>>> other platforms that do not readily support /etc/hosts-formatted files.
>>> In all honesty I never considered a Java DNS implementation that could
>>> simply run in a separate thread. That is something that I will
>>> definitely look into.
>>>
>>> As for the files themselves, these do go into the app-local data
>>> directories. The installation definitely does not pollute the OS file
>>> system beyond that. I'm sorry if there was confusion in my previous
>>> email regarding that point.
>>>
>>> Will
>>>
>>> On 05/15/2012 12:09 PM, Hans-Christoph Steiner wrote:
>>>>
>>>> Sounds good.  Is this setup meant to be only for Android or other platforms too?  I ask because it'll probably be easier to manage a pure Java DNS server as an Android Service than adding another C binary.
>>>>
>>>> As for writing out a non-standard file like /etc/hosts-formatted, if you are writing a custom file, then it should go into the app's file hierarchy.  It is important to avoid touching the filesystem as much as possible.  This file could go into /data/data/net.szym.barnacle/app_bin or we could create ...../app_etc or something like that.
>>>>
>>>> .hc
>>>>
>>>> On May 14, 2012, at 4:22 PM, Will Hawkins wrote:
>>>>
>>>>> Hello all!
>>>>>
>>>>> I just wanted to give everyone an update on what's going on here: I am
>>>>> working on adding capability to the client to handle DNS entries
>>>>> distributed in the mesh (via olsr nameservice plugin). Because Android's
>>>>> /etc/hosts file is on the readonly file system, simply telling olsrd to
>>>>> write out an /etc/hosts file (like it would normally do on a *nix host)
>>>>> does not work.
>>>>>
>>>>> So, I cross-compiled a small (300k) DNS server that the app invokes when
>>>>> the user connects to the mesh. This server answers queries by first
>>>>> looking for an answer in an /etc/hosts-formatted file. If there are no
>>>>> matches, the DNS server forwards the request.
>>>>>
>>>>> In my testing it works fairly well. I am still integrating it into the
>>>>> build but I wanted to give everyone an update.
>>>>>
>>>>> Talk to you all soon!
>>>>> Will
>>>>> _______________________________________________
>>>>> Commotion-dev mailing list
>>>>> Commotion-dev at lists.chambana.net
>>>>> http://lists.chambana.net/mailman/listinfo/commotion-dev
>>>>>
>>>>
>>>>
>>>
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>>
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