From owner-freebsd-net@FreeBSD.ORG  Tue Feb  9 18:09:03 2010
Return-Path: <owner-freebsd-net@FreeBSD.ORG>
Delivered-To: net@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 49DC5106566B
	for <net@freebsd.org>; Tue,  9 Feb 2010 18:09:03 +0000 (UTC)
	(envelope-from qing.li@bluecoat.com)
Received: from whisker.bluecoat.com (whisker.bluecoat.com [216.52.23.28])
	by mx1.freebsd.org (Postfix) with ESMTP id 347488FC0C
	for <net@freebsd.org>; Tue,  9 Feb 2010 18:09:01 +0000 (UTC)
Received: from bcs-mail03.internal.cacheflow.com ([10.2.2.95])
	by whisker.bluecoat.com (8.14.2/8.14.2) with ESMTP id o19I8ijP025933;
	Tue, 9 Feb 2010 10:08:44 -0800 (PST)
X-MimeOLE: Produced By Microsoft Exchange V6.5
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Date: Tue, 9 Feb 2010 10:05:10 -0800
Message-ID: <B583FBF374231F4A89607B4D08578A43046737A7@bcs-mail03.internal.cacheflow.com>
X-MS-Has-Attach: 
X-MS-TNEF-Correlator: 
Thread-Topic: struct sockaddr * and alignment
Thread-Index: Acqpr4wkT9PnCl9mR4yZk0PbiugUKwAAt7/2
References: <20100209.103411.506052712871889475.imp@bsdimp.com>
From: "Li, Qing" <qing.li@bluecoat.com>
To: "M. Warner Losh" <imp@bsdimp.com>, <net@freebsd.org>
Cc: 
Subject: RE: struct sockaddr * and alignment
X-BeenThere: freebsd-net@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net>
List-Post: <mailto:freebsd-net@freebsd.org>
List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 09 Feb 2010 18:09:03 -0000


>
> Sure enough, that fixes this warning.  Yea.  But, sadly, it causes
> other problems.  If you look at sbin/atm/atmconfig/natm.c you'll see
> code like:
>=20
> static void
> store_route(struct rt_msghdr *rtm)
> {
> ...
> 	char *cp
> 	struct sockaddr *sa;
> 	...
>=20
> 	cp =3D (char *)(rtm + 1);
> ...
> 			sa =3D (struct sockaddr *)cp;
> 			cp +=3D roundup(sa->sa_len, sizeof(long));
> ...
>=20
> which breaks because we're now casting from an __aligned(1) char * to
> an __aligned(8) sockaddr *.

> And it is only rounding the size of the structure to long, rather than
> int64 like sockaddr_storage suggests is the proper alignment.  But I
> haven't looked in the kernel to see if there's an issue there with
> routing sockets or not.
>=20

In the kernel route.h, the macro SA_SIZE is used by the routing socket
code and may the root of the problem.

-- Qing