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List:       ipng
Subject:    (IPng 4570) Re: Update to RFC 2133
From:       thartric () mentat ! com (Tim Hartrick)
Date:       1997-09-26 23:07:17
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Jim,

> 
> I know those applications do exist.  So I may be able to absorb this
> conclusion too if we have an MT safe gethostbyname2() as I said in
> previous mail and for the reasons I already stated.  I essentially want
> some control over whats in the resolver library specified and that can
> be used by those who don't want all getaddrinfo() has to offer.  
>

Yes I am fairly certain that there are old pieces of code laying around
that do longjmps without having a easy way to add the memory clean-up.

Unfortunately I don't see how you get to a MT safe gethostbyname[2] type
facility without inventing a new set of API's in addition to getaddrinfo
which is MT safe and the existing non MT safe gethostbyname.

That would mean something like Erik's or Harvey's suggestion.  That is
doable but it means inventing another wheel.

In one of your previous notes you indicated that ISV's want a simple
replacement for the existing gethostbyname facilities.  Simple would imply
that at least initially they don't care about nor do they want to spend
time worrying about MT safety.

Given that I would propose the following.

1) We define a non MT safe version of gethostbyname[2] which can be used
   by ISV who are looking for the quick fix.  The simplest thing to do here
   is simply use gethostbyname2 as it has been defined in the current BIND
   distribution.

   I believe this would satisfy the original requirements of the API.

> 
>   1. get ipv4 addresses
>   2. get ipv4 mapped addresses
>   3. get ipv6 addresses
> 

2) We add whatever options we believe are necessary to getaddrinfo to make
   it a complete solution for IPv6 addressing and call that the MT safe
   API.

The problems with this include:

1) Some folks believe that gethostbyname2 is a kludge.

2) We do not have an IPv4/IPv6 MT safe API on which to base an implementation
   of getaddrinfo.


These might be showstoppers.  I don't know.  It would be nice to limit
ourselves to at most two ways to get the job done.  An MT safe way and
a non MT safe way.  If we could get it down to one (getaddrinfo) that
would probably be ideal from an implementation point of view but maybe
not so ideal from the perspective of ISV's.



tim
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