Re: [squid3-ipv6] dns_internal.cc

From: Rafael Martinez \(Squid development\) <rmartine@dont-contact.us>
Date: Mon, 26 Nov 2007 16:06:01 +0100

>
> > imasd.ipv6.elmundo.es will fire an error, even with n=4 ...
>
> which error ?
>

(debug_options 78,9 )

2007/11/26 15:48:37.010| idnsALookup: buf is 39 bytes for
imasd.ipv6.elmundo.es, id = 0xa80c
2007/11/26 15:48:37.010| idnsRead: starting with FD 7
2007/11/26 15:48:37.021| idnsRead: FD 7: received 325 bytes from
62.42.230.24:53
2007/11/26 15:48:37.021| idnsGrokReply: ID 0xa80c, 4 answers
==========================================================================
2007/11/26 15:48:37.021| idnsGrokReply: imasd.ipv6.elmundo.es AAAA query
failed. Trying A now instead.
===========================================================================
2007/11/26 15:48:37.021| idnsRead: starting with FD 7
2007/11/26 15:48:37.050| idnsRead: FD 7: received 100 bytes from
62.42.63.52:53
2007/11/26 15:48:37.050| idnsGrokReply: ID 0xeb37, 0 answers

> >
> > host -t AAAA imasd.ipv6.elmundo.es
> > imasd.ipv6.elmundo.es has IPv6 address 2001:450:9:10::115
> > imasd.ipv6.elmundo.es has IPv6 address 2001:800:400:10::71
> > imasd.ipv6.elmundo.es has IPv6 address 2001:800:400:10::115
> > imasd.ipv6.elmundo.es has IPv6 address 2001:450:9:10::71
> >
> >

>
> > Should it be fixed to ? recall the && instead of || .
> > ---
> >> if(q->need_A && (Config.onoff.dns_require_A == 1 && n <= 0 ) )
> No. I initially had it with two &&. But it turns out that when IPv6 are
> provided but not working we need to be able to fallback to the IPv4.
> That is getting rarer, but still may occur due to any number of network
> issues.
> If the IPv4 are not placed into cache at the time of lookup squid trusts
> its existing (v6) results and returns a false-error page.
>
> ... getting on and commenting the code to that effect ...
>
>
Right. But the above log error is invoked with state:

q->need_A = 1 , Config.onoff.dns_require_A == 1 , n = 4

evaluating the "if" guard to true. And the message is

"idnsGrokReply: imasd.ipv6.elmundo.es AAAA query failed"

> >
> > Even with that, ipcache.cc seems to have problems with canonical
> > names...
>
> Any more detail on what those problems are?
> I have seen some weird behaviour listing ipcache, but nothing I have
> been able to track down yet. If you can provide any light all the
> better. My bug has something to do with walking the hash list under some
> still unknown conditions.
>

Yes, it's about that, (a flag?) When I get a deeper knowledge I'll
write..
Meanwhile, if you locally modify the || by && (just to test, perhaps
this is not the rigth solution, up to you) , you can reproduce the
failure by entering a non-canonical name, i.e. www.google.com ,
www.ipv6.elmundo.es , (no matter if IPv4 or IPv6) . By contrast,
www.l.goggle.com and imasd.ipv6.elmundo.es, canonical names, seem to be
answered...
Received on Mon Nov 26 2007 - 08:06:24 MST

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