[reSIProcate] [Patch] Sketch of patch for adding c-ares 1.5.x support

[Adam Roach]

Frankly, my inclination in the short term would be to rename our symbols 
from "ares_" to "rares_" or something simple and mechanical like that. I 
suspect a full merge of the functionality we need for resip into c-ares 
would be a non-trivial task.

/a

Byron Campen wrote:
>     Wow. So, it is my understanding that we've added a few unusual 
> features to our copy of ares, that I'm not sure would be ready to 
> merge back into c-ares. I haven't really touched our copy of ares.
>
>     Derek, what are your thoughts on this?
>
> Best regards,
> Byron Campen
>
>> Hi.  I'm new to resiprocate, and from what I've seen so far, it's one
>> of the best SIP stacks I've worked with.  Nice work!
>>
>> I've run into one minor snag, though.  Our infrastructure here uses
>> c-ares 1.5.x to do its asynchronous DNS lookups.  That library,
>> maintained at <http://c-ares.haxx.se/>, has come a good distance from
>> the original ares library that is used in resiprocate.
>> Coincidentally, I've contributed a few patches to that project as
>> well.
>>
>> This wouldn't really be a problem, except the symbols used in c-ares
>> and ares are the same: in both they all start with ares_, and in fact
>> they generally are pretty much the same.  So, this meant that I was
>> maximally out of luck; if resiprocate or I had used any other DNS
>> resolvers, we'd be fine to cooperate, but things are just too similar
>> to work :)
>>
>> Since c-ares has at least some IPv6 support and aims to work on Win32
>> as well as POSIX, I figured I'd solve this just by using c-ares
>> instead of the contrib/ares that comes with resiprocate, thus this
>> sketch of a patch in progress.  I'm hoping the folks on this list can
>> guide me towards a final patch that is good enough to include in
>> resiprocate itself.
>>
>> What I've done so far:
>>
>> - Started with the 1.4 release (instead of svn) since I'm new to the
>>   project and wanted to keep things simple.  Hopefully, there is
>>   little volatility in this area, though.
>>
>> - Tried to hide almost all the differences between the library in a
>>   new header, rutil/dns/AresCompat.hxx that is included only in .cxx
>>   files.  In particular, the patch aims to not require including code
>>   to define USE_ARES or USE_CARES in order to _use_ the library or
>>   its headers, although a built library will be wired permanently to
>>   one or the other.
>>
>> - Adapted the initialization and callback code to work with the
>>   slightly new (improved?) c-ares API
>>
>> - Added rules to configure and the Makefiles to allow an external
>>   c-ares installation to be used instead contrib/ares with minimal
>>   pain outside of the rutil/dns/ directory.
>>
>> - Got things roughly working with the stack/ test tools.
>>
>> - Left some TODOs for things that are currently hard or impossible to
>>   do in c-ares, or that I didn't understand (see the patch)
>>
>> - Probably made a mess of it :)
>>
>> Clearly, the resiprocate version of ares hasn't stood still, so its
>> version is also "a better ares", and so there are few things that
>> resiprocate does that c-ares doesn't have support for right this
>> minute.  The c-ares maintainers are good folks, though, so I'm sure if
>> there are any really important things that need adding, they'd
>> consider it.  Even though I'm brand new to resiprocate, I'd be happy
>> to help apply any patches to c-ares that would help make it more
>> usable by the mainstream resiprocate version.
>>
>> As I said, I'd love to be able to get this draft patch to the point
>> where it could be accepted into resiprocate.  Thanks in advance for
>> any feedback!
>>
>> -- 
>> ----------------------------------------------------------
>> Brad Spencer - spencer at starscale.com - www.starscale.com
>> <cares-support.diff>_______________________________________________
>> resiprocate-devel mailing list
>> resiprocate-devel at resiprocate.org
>> https://list.resiprocate.org/mailman/listinfo/resiprocate-devel
>
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