Date: Sat, 2 Nov 2013 09:32:45 +0000 From: Mark R V Murray <mark@grondar.org> To: Adrian Chadd <adrian@freebsd.org> Cc: "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>, Bruce Evans <brde@optusnet.com.au> Subject: Re: svn commit: r257535 - head/sys/netgraph Message-ID: <76BC3F76-ED5E-42F0-BCCE-271EA723698E@grondar.org> In-Reply-To: <CAJ-VmokeP5Z2d7jZ-j-Thrh_VuQBKGpKC9nWG%2BQfhR0f6wzF9w@mail.gmail.com> References: <201311020011.rA20BchL020170@svn.freebsd.org> <20131102151309.A1102@besplex.bde.org> <CAJ-VmokeP5Z2d7jZ-j-Thrh_VuQBKGpKC9nWG%2BQfhR0f6wzF9w@mail.gmail.com>
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[-- Attachment #1 --] On 2 Nov 2013, at 05:53, Adrian Chadd <adrian@freebsd.org> wrote: > Hm! A good question! > > On 1 November 2013 22:22, Bruce Evans <brde@optusnet.com.au> wrote: > >>> if (harvest.point_to_point) >>> - random_harvest(&(m->m_data), 12, 2, RANDOM_NET_NG); >> >> >> '&(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()). >> >> >>> + random_harvest(mtod(m, const void *), 12, 2, >>> RANDOM_NET_NG); >> >> >> 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. >> > > > 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’t have 12-byte pointers in FreeBSD. :-) M -- Mark R V Murray [-- Attachment #2 --] -----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-----help
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