From owner-freebsd-net@FreeBSD.ORG Mon Jan 23 22:57:18 2006 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3B20116A422 for ; Mon, 23 Jan 2006 22:57:18 +0000 (GMT) (envelope-from gregorynou@altern.org) Received: from esemetz.metz.supelec.fr (esemetz.metz.supelec.fr [193.48.224.212]) by mx1.FreeBSD.org (Postfix) with ESMTP id 43DCB43DE1 for ; Mon, 23 Jan 2006 22:24:58 +0000 (GMT) (envelope-from gregorynou@altern.org) Received: from smtp.metz.supelec.fr (smtp.metz.supelec.fr [193.48.224.205]) by esemetz.metz.supelec.fr (8.11.6/8.9.3) with ESMTP id k0NMOtY12814 for ; Mon, 23 Jan 2006 23:24:56 +0100 Received: from [193.48.225.2] (nou.rez-metz.supelec.fr [193.48.225.2]) by smtp.metz.supelec.fr (8.11.6/8.11.6) with ESMTP id k0NMEsB11846 for ; Mon, 23 Jan 2006 23:14:54 +0100 Message-ID: <43D557B0.2080306@altern.org> Date: Mon, 23 Jan 2006 23:24:48 +0100 From: Gregory Nou User-Agent: Thunderbird 1.5 (X11/20060113) MIME-Version: 1.0 To: freebsd-net@freebsd.org Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Question on VLAN X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 23 Jan 2006 22:57:18 -0000 Hi, What is the difference between if (m->m_flags & M_VLANTAG) and if (ether_type == ETHERTYPE_VLAN) ? I suppose that m->m_flags are set using ether_type at one point. Still, I was not able to find a location in the source where it would happen. The fact is, I do not understand the difference between these two things, nor do I understand why we need the code in if_ethersubr.c[691-717] Thanks a lot ! -- Gregory