Date: Wed, 20 Sep 2006 17:26:26 +1000 From: Peter Jeremy <peterjeremy@optushome.com.au> To: Jung-uk Kim <jkim@freebsd.org> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org, John Baldwin <jhb@freebsd.org> Subject: Re: cvs commit: src/sys/dev/bge if_bge.c Message-ID: <20060920072626.GA738@turion.vk2pj.dyndns.org> In-Reply-To: <200609191535.08184.jkim@FreeBSD.org> References: <200609182218.k8IMIMUT059300@repoman.freebsd.org> <200609191431.01649.jkim@FreeBSD.org> <20060919190449.GC720@turion.vk2pj.dyndns.org> <200609191535.08184.jkim@FreeBSD.org>
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--Q68bSM7Ycu6FN28Q Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, 2006-Sep-19 15:35:06 -0400, Jung-uk Kim wrote: [VLAN tagging] >Why don't we just fake it up from ether_input() and pass it to=20 >BPF_MTAP() instead of 'teaching' bpf? I think it is more logical=20 >thing to do. As Andre points out, this negates the benefit of IFCAP_VLAN_HWTAGGING. In addition, the code necessary to correctly re-insert the VLAN tag (to provide a fully valid mbuf chain for further processing) will be larger and slower than the code necessary to kludge a mbuf that is adequate for bpf_filter(). bpf_mtap2() provides an example of kludging an mbuf header to allow data to be pre-pended. The code to kludge up the VLAN tag insertion would be similar (though somewhat more complex). Overall, I believe this approach is probably preferable to just disabling hardware VLAN tagging if there is a bpf filter. --=20 Peter Jeremy --Q68bSM7Ycu6FN28Q Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (FreeBSD) iD8DBQFFEO0i/opHv/APuIcRAuNSAJ0XAFeUznlXYBKCpAxM3GM/pBALdQCeMOz9 JO0pLra3AhjtfufsAT8z+1Y= =Ekb2 -----END PGP SIGNATURE----- --Q68bSM7Ycu6FN28Q--
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