X-Recipient:	archive-cygwin AT delorie DOT com
DomainKey-Signature:	a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:date:from:to:subject:message-id:reply-to
	:references:mime-version:content-type:in-reply-to; q=dns; s=
	default; b=RW4rLYb4FQiNByaqQsUUbbb89b5xjP/eTNJdcMrwililxIr0mYrx9
	3acxJ2UXUOzQgKJ5KyTji63euaWm3n2NmkvEVKaqSvmVY3PLb1rEkt6Y4150QJ6C
	U7GPe45SqCNG75LlOeaxZ0g66VSZgvLW9FZfvUCr1fZQ4ZKtt6cWNE=
DKIM-Signature:	v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:date:from:to:subject:message-id:reply-to
	:references:mime-version:content-type:in-reply-to; s=default;
	bh=DzXD8+NFGH0uO2i0bETNcZ/HwTc=; b=L4KfzT2mmXO+ieWe3PjDFhwcvlZR
	kJ92CNovGoWT+0IGmG4zDUFGDAqN9HKWYAgexpVns722QLVN95iYPl8tvLN6eLuR
	zVrBLMZzUKLyu9p9m6xP6FznytYYwQa/F/sUSx3tJSeFWCsqT2lMW1CfD6k4pXB8
	FtzQYj8t6MjuTXA=
Mailing-List:	contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id:	<cygwin.cygwin.com>
List-Subscribe:	<mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive:	<http://sourceware.org/ml/cygwin/>
List-Post:	<mailto:cygwin AT cygwin DOT com>
List-Help:	<mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender:	cygwin-owner AT cygwin DOT com
Mail-Followup-To:	cygwin AT cygwin DOT com
Delivered-To:	mailing list cygwin AT cygwin DOT com
Authentication-Results:	sourceware.org; auth=none
X-Virus-Found:	No
X-Spam-SWARE-Status:	No, score=-5.9 required=5.0 tests=AWL,BAYES_00 autolearn=ham version=3.3.2
X-HELO:	calimero.vinschen.de
Date:	Thu, 8 Jan 2015 14:23:53 +0100
From:	Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To:	cygwin AT cygwin DOT com
Subject:	Re: Resolving localhost on Windows 7 (for exim)
Message-ID:	<20150108132353.GN4190@calimero.vinschen.de>
Reply-To:	cygwin AT cygwin DOT com
Mail-Followup-To:	cygwin AT cygwin DOT com
References:	<0NHP009ITJ361TD0 AT vms173009 DOT mailsrvcs DOT net>
MIME-Version:	1.0
In-Reply-To:	<0NHP009ITJ361TD0@vms173009.mailsrvcs.net>
User-Agent:	Mutt/1.5.23 (2014-03-12)

--l7GkBbkEatsaRqBf
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

Hi Pierre,

On Jan  5 09:03, Pierre A. Humblet wrote:
> While porting exim to Windows 64 I have observed strange results when
> resolving localhost
>=20
> On Windows XP,
>=20
> Resolv: search "localhost" type 28
> Resolv: query "localhost" type 28
> Resolv: DnsQuery: 0 (Windows)
> Resolv: localhost Section 0 Type 28 Windows Record Length 16
> 08:02:06  3760 DNS lookup of localhost (AAAA) succeeded
> Resolv: search "localhost" type 1
> Resolv: query "localhost" type 1
> Resolv: DnsQuery: 0 (Windows)
> Resolv: localhost Section 1 Type 1 Windows Record Length 4
> 08:44:13  5552 DNS lookup of localhost (A) succeeded
>=20
> We see that for IPV4 localhost things are fine.
> Windows returns an answer section (1) and Cygwin processes it correctly.
>=20
> However for IPV6 it returned a question section (0) but with data in it.
> Cygwin essentially drops that.
> That's why above the application tried an A record after getting the AAAA
> record, which was empty.
>=20
>=20
> However of Windows 7
> CYGWIN_NT-6.1 Dell3020 1.7.33-2(0.280/5/3) 2014-11-13 15:47 x86_64 Cygwin
>=20
> Resolv: search "localhost" type 28
> Resolv: query "localhost" type 28
> Resolv: DnsQuery: 0 (Windows)
> Resolv: localhost Section 0 Type 28 Windows Record Length 16
> 08:22:24 140244 DNS lookup of localhost (AAAA) succeeded
> Resolv: search "localhost" type 1
> Resolv: query "localhost" type 1
> Resolv: DnsQuery: 0 (Windows)
> Resolv: localhost Section 0 Type 1 Windows Record Length 4
>=20
> We see that Windows returns question sections in both cases and localhost=
 is
> never resolved.
> From what I have seen Windows never returns question section in normal ca=
ses
> so I suggest
> inserting the following on line 251 of minires-os-if.c, to essentially tu=
rn
> question sections
> in answer sections (after  while (rr) { )
>=20
> if ((rr->Flags.DW & 0x3) =3D=3D 0) {
>         DPRINTF(debug, "Got section 0 %s %d with data length %d\n", DomNa=
me,
> Type, rr->wDataLength);
>         if (rr->wDataLength > 0)
>                 rr->Flags.DW |=3D 1; // Make it an answer section as ther=
e is
> data
> }

Can you please send at least a real patch?  Without the formatting
matching the surrounding code I'm totally unsure where to apply this
code.  A ChangeLog entry would be helpful as well.

> It would be nice if this would be tried ASAP.
> However I am not setup currently to build cygwin.

It's not exactly tricky to set this up...

> Occasionally I also see localhost queries fail.
> I have not been able to pinpoint what causes that.
>=20
> Resolv: search "localhost" type 28
> Resolv: query "localhost" type 28
> Resolv: DnsQuery: 9003 (Windows)
> 08:00:14 145640 DNS lookup of localhost (AAAA) gave HOST_NOT_FOUND
> 08:00:14 145640 returning DNS_NOMATCH
> Resolv: search "localhost" type 1
> Resolv: query "localhost" type 1
> Resolv: DnsQuery: 9003 (Windows)
>=20
>=20
> In light of RFC 6761 we should handle localhost in gethostbyname2, for bo=
th
> IP4 and IP6
> While we are at it we should also handle numerical domains w.x.y.z there.
> That's less urgent, I can do that in the coming weeks.

Cool, I'm looking forward to your patches!


Thanks,
Corinna

--=20
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

--l7GkBbkEatsaRqBf
Content-Type: application/pgp-signature

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
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=l/wh
-----END PGP SIGNATURE-----

--l7GkBbkEatsaRqBf--

- Raw text -