Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758050AbXEZINt (ORCPT ); Sat, 26 May 2007 04:13:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752840AbXEZINh (ORCPT ); Sat, 26 May 2007 04:13:37 -0400 Received: from stinky.trash.net ([213.144.137.162]:52420 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751468AbXEZINg (ORCPT ); Sat, 26 May 2007 04:13:36 -0400 Message-ID: <4657EC24.1030407@trash.net> Date: Sat, 26 May 2007 10:13:24 +0200 From: Patrick McHardy User-Agent: Debian Thunderbird 1.0.7 (X11/20051017) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Adam Osuchowski CC: Stephen Hemminger , bridge@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [Bridge] [BUG] Dropping fragmented IP packets within VLAN frames on bridge References: <20070525081750.5ba4a411@zonk.pl> <20070525085947.12841835@freepuppy> <20070525174925.41bd6b2e@zonk.pl> In-Reply-To: <20070525174925.41bd6b2e@zonk.pl> X-Enigmail-Version: 0.93.0.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1408 Lines: 39 Adam Osuchowski wrote: > Stephen Hemminger wrote: > >>It would be better to account for the tag in the length check. >>Something like >> if (skb->protocol == htons(ETH_P_IP) && >> skb->len > skb->dev->mtu - (IS_VLAN_IP(skb) ? VLAN_HLEN : 0) && >> !skb_is_gso(skb)) >> return ip_fragment ... > > > It isn't good solution because one of IS_VLAN_IP() necessary condition is > > skb->protocol == htons(ETH_P_8021Q) > > which is, of course, mutually exclusive with > > skb->protocol == htons(ETH_P_IP) > > from br_nf_dev_queue_xmit(). IMHO, one should check length of ETH_P_IP > and ETH_P_8021Q frames separately: > > if (((skb->protocol == htons(ETH_P_IP) && skb->len > skb->dev->mtu) || > (IS_VLAN_IP(skb) && skb->len > skb->dev->mtu - VLAN_HLEN)) && > !skb_is_gso(skb)) > return ip_fragment ... net/8021q ignores the VLAN header overhead, so we should probably do the same here for consistency. Using IS_VLAN_IP (and IS_PPPOE_IP for current -rc) looks fine, additionally we should probably also check for skb->nfct != NULL to make sure that at least without connection tracking the bridge doesn't perform fragmentation. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/