X-Recipient: archive-cygwin AT delorie DOT com
X-Spam-Check-By: sourceware.org
Date: Sat, 5 Sep 2009 18:12:29 +0200
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: missing ipi_spec_dst in struct in_pktinfo
Message-ID: <20090905161229.GA1869@calimero.vinschen.de>
Reply-To: cygwin AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
References: <OF10653B86 DOT 82265559-ON85257627 DOT 006D9ED5-85257627 DOT 006ED0E7 AT epamail DOT epa DOT gov>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <OF10653B86.82265559-ON85257627.006D9ED5-85257627.006ED0E7@epamail.epa.gov>
User-Agent: Mutt/1.5.19 (2009-02-20)
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
Precedence: bulk
List-Id: <cygwin.cygwin.com>
List-Unsubscribe: <mailto:cygwin-unsubscribe-archive-cygwin=delorie DOT com AT cygwin DOT 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

On Sep  4 16:10, Schulman DOT Andrew AT epamail DOT epa DOT gov wrote:
> 
> I'm trying to build socat for Cygwin (1.7).  The build fails with
> 
> xio-ip.c:480: error: structure has no member named `ipi_spec_dst'
> 
> The offending code wants to use pktinfo->ipi_spec_dst.s_addr, where
> pktinfo is a struct in_pktinfo *.  The problem is that in Cygwin,
> in_pktinfo doesn't have an ipi_spec_dst member.  The IP man page
> (http://homepages.cwi.nl/~aeb/linux/man2html/man7/ip.7.html) lists
> in_pktinfo as
> 
> struct in_pktinfo {
>     unsigned int   ipi_ifindex;  /* Interface index */
>     struct in_addr ipi_spec_dst; /* Local address */
>     struct in_addr ipi_addr;     /* Header Destination address */
> };
> 
> while in /usr/include/cygwin/in.h, it's just
> 
> struct in_pktinfo
> {
>   struct in_addr ipi_addr;
>   uint32_t       ipi_ifindex;
> };
> 
> Any suggestions for a workaround to this problem?  Why is ipi_spec_dst
> missing, and more to the point, what can/should I substitute in its
> place?

ipi_spec_dst is missing because the Winsock structure in_pktinfo is
defined without this field.  The recvmsg function will return the
Winsock equivalent to this structure, since that's how it gets it from
Windows.  The workaround is easy: Don't use that field.  Disable the code
in socat which uses it.  Even if we would go to great lengths to
add/remove the field when calling WSASendMsg/WSARecvMsg, it would be
entirely meaningless anyway.


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          cygwin AT cygwin DOT com
Red Hat

--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple