Date: Mon, 25 Aug 2008 21:02:07 +0200 From: John Hay <jhay@meraka.org.za> To: gnn@FreeBSD.org Cc: Luigi Rizzo <rizzo@iet.unipi.it>, "Bruce M. Simpson" <bms@FreeBSD.org>, net@FreeBSD.org Subject: Re: Small patch to multicast code... Message-ID: <20080825190207.GA73478@zibbi.meraka.csir.co.za> In-Reply-To: <m28wuohfm5.wl%gnn@neville-neil.com> References: <m27iaa6v43.wl%gnn@neville-neil.com> <20080821203519.GA51534@onelab2.iet.unipi.it> <m23aky6ncl.wl%gnn@neville-neil.com> <48AE23FF.9070009@FreeBSD.org> <m2tzdd6j36.wl%gnn@neville-neil.com> <48AF08B7.4090804@FreeBSD.org> <m2fxowhgq8.wl%gnn@neville-neil.com> <48AF330B.4010802@FreeBSD.org> <m28wuohfm5.wl%gnn@neville-neil.com>
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On Fri, Aug 22, 2008 at 03:03:30PM -0700, gnn@FreeBSD.org wrote: > At Fri, 22 Aug 2008 22:43:39 +0100, > Bruce M. Simpson wrote: > > > > gnn@FreeBSD.org wrote: > > > Somehow the data that the device needs to do the proper checksum > > > offload is getting trashed here. Now, since it's clear we need a > > > writable packet structure so that we don't trash the original, I'm > > > wondering if the m_pullup() will be sufficient. > > > > > > > If it's serious enough to break UDP checksumming on the wire, perhaps we > > should just swallow the mbuf allocator heap churn and do the m_dup() for > > now, but slap in a big comment about why it's there. > > I think if none of us finds a better way before early next week that's > what I'll do so that this at least works in 7.1. I think we and others have been hitting this problem: kern/119635: [em] Bad UDP packet checksum with em(4) and rxcsum/txcsum enabled http://www.freebsd.org/cgi/query-pr.cgi?pr=119635 I'll try out your patch. John -- John Hay -- John.Hay@meraka.csir.co.za / jhay@FreeBSD.org
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