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From: Tollef Fog Heen <tfheen@err.no>
To: dev@apr.apache.org
Subject: Re: getaddrinfo on Ubuntu
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Date: Thu, 07 Jun 2007 08:41:24 +0200
In-Reply-To: <20070606211840.GB18044@redhat.com> (Joe Orton's message of "Wed,
	6 Jun 2007 22:18:41 +0100")
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* Joe Orton 

| But yes, testsockets.c will need some tweaking to cope with this 
| getaddrinfo implementation.  I think it's caused by an Ubuntu patch, if 
| I read https://bugs.launchpad.net/ubuntu/+source/netcfg/+bug/24828 
| correctly.  It might break some applications in fun ways too, but 
| there's not much APR can do about that.

FWIW, I have yet to see any bug reports about anything breaking with
this, except testsockets.c.

What the glibc patch does is it only returns IPv6 addresses if they
are explicitly requested by the application or you have an IPv6
address with a scope of < link (that is, if you have site or global
scope address).

The reason for the patch is lots of cheap DSL routers seem to just not
respond to AAAA or A6 queries, so applications would try to resolve a
name, glibc would send out an AAAA query, wait for it to time out,
then send out an A request instead of just getting a NXDOMAIN or
similar back immediately.  So, it's a hack for brokenness in lots of
software which is not Ubuntu's, but it makes the user experience much
better without breaking IPv6 for those who actually use it.

Whether it should treat numeric addresses specifically is something I
had not considered; maybe it should.  I would be happy to receive
feedback on this.  On the other hand, I would suspect the number of
people keying in IPv6 addresses into their applications and not having
a site or global IPv6 address to be fairly small so real-world
breakage should be limited.

-- 
Tollef Fog Heen
UNIX is user friendly, it's just picky about who its friends are