From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH -next, V3 0/2] net: force refragmentation for DF reassembed skbs Date: Wed, 27 May 2015 13:04:01 -0400 (EDT) Message-ID: <20150527.130401.726728313381454100.davem@davemloft.net> References: <1432305171-21932-1-git-send-email-fw@strlen.de> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, hannes@stressinduktion.org To: fw@strlen.de Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:37268 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751600AbbE0REE (ORCPT ); Wed, 27 May 2015 13:04:04 -0400 In-Reply-To: <1432305171-21932-1-git-send-email-fw@strlen.de> Sender: netdev-owner@vger.kernel.org List-ID: From: Florian Westphal Date: Fri, 22 May 2015 16:32:49 +0200 > output path tests: > > if (skb->len > mtu) ip_fragment() > > This breaks connectivity in one corner case: > If the skb was reassembled, but has the DF bit set and .. > .. its reassembled size is <= outdev mtu .. > .. we will forward a DF packet larger than what the sender > transmitted on wire. > > If a router later in the path can't forward this packet, it will send an > icmp error in response to an mtu that the original sender never exceeded. > > This changes ipv4 defrag/output path to > > a) force refragmentation for DF reassembled skbs and > b) set DF bit on all fragments when refragmenting if it was set on original > frags. ... Series applied, thanks Florian.