From owner-svn-src-all@FreeBSD.ORG Sat Nov 2 09:32:59 2013 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 1BFC645C; Sat, 2 Nov 2013 09:32:59 +0000 (UTC) (envelope-from mark@grondar.org) Received: from gromit.grondar.org (grandfather.grondar.org [IPv6:2a01:348:0:15:5d59:5c20:0:2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id D38302B1A; Sat, 2 Nov 2013 09:32:58 +0000 (UTC) Received: from [2001:470:9174:1:c021:148:e570:f34] by gromit.grondar.org with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.80.1 (FreeBSD)) (envelope-from ) id 1VcXZe-000130-Dx; Sat, 02 Nov 2013 09:32:55 +0000 Subject: Re: svn commit: r257535 - head/sys/netgraph Mime-Version: 1.0 (Mac OS X Mail 7.0 \(1816\)) Content-Type: multipart/signed; boundary="Apple-Mail=_D4051F9E-885D-4EA1-864C-1D8BE058937F"; protocol="application/pgp-signature"; micalg=pgp-sha512 From: Mark R V Murray In-Reply-To: Date: Sat, 2 Nov 2013 09:32:45 +0000 Message-Id: <76BC3F76-ED5E-42F0-BCCE-271EA723698E@grondar.org> References: <201311020011.rA20BchL020170@svn.freebsd.org> <20131102151309.A1102@besplex.bde.org> To: Adrian Chadd X-Mailer: Apple Mail (2.1816) X-SA-Score: -1.0 Cc: "svn-src-head@freebsd.org" , "svn-src-all@freebsd.org" , "src-committers@freebsd.org" , Bruce Evans X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 02 Nov 2013 09:32:59 -0000 --Apple-Mail=_D4051F9E-885D-4EA1-864C-1D8BE058937F Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 On 2 Nov 2013, at 05:53, Adrian Chadd wrote: > Hm! A good question! >=20 > On 1 November 2013 22:22, Bruce Evans wrote: >=20 >>> if (harvest.point_to_point) >>> - random_harvest(&(m->m_data), 12, 2, RANDOM_NET_NG); >>=20 >>=20 >> '&(m->m_data)' is not just a pair of style bugs. It gives address of >> the pointer (somewhere in the mbuf header), not the address of = pointed- >> to data, so the randomness was almost null. The style bugs are >> excessive parentheses and chumminess with the implementation (non-use >> of the accessor function mtod()). >>=20 >>=20 >>> + random_harvest(mtod(m, const void *), 12, 2, >>> RANDOM_NET_NG); >>=20 >>=20 >> Presumably you really do want to harvest the pointed-to data and = there >> are at least 12 bytes of it, so the semantic fix isn't backwards or a >> buffer overrun. >>=20 >=20 >=20 > Mark - did you initially mean the address of the mbuf m_data pointer, > or the data payload itself? As Bruce says - the address of payload data itself. We don=92t have = 12-byte pointers in FreeBSD. :-) M --=20 Mark R V Murray --Apple-Mail=_D4051F9E-885D-4EA1-864C-1D8BE058937F Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP using GPGMail -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.22 (Darwin) Comment: GPGTools - http://gpgtools.org iQCVAwUBUnTGwt58vKOKE6LNAQpBTAQAkGQL2BwjbjUAOqhUGilLE6caZuz40QmX kdHOrG3tyrVxQDVWbbkDEACpQ7ih9R4fsGPL/nA24KcS1N8bYKwXPrN3axGYfLMA OLgi5rX3yP4yw51rctQVUee6zCoLDeb36afL//h1JtQDIUg01e85PAQieNASyAG/ 73om+84TZe8= =a0EQ -----END PGP SIGNATURE----- --Apple-Mail=_D4051F9E-885D-4EA1-864C-1D8BE058937F--