Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756073AbcJ3DBI (ORCPT ); Sat, 29 Oct 2016 23:01:08 -0400 Received: from shards.monkeyblade.net ([184.105.139.130]:55482 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753853AbcJ3DBG (ORCPT ); Sat, 29 Oct 2016 23:01:06 -0400 Date: Sat, 29 Oct 2016 23:01:04 -0400 (EDT) Message-Id: <20161029.230104.141605741908542764.davem@davemloft.net> To: stefanr@s5r6.in-berlin.de Cc: netdev@vger.kernel.org, linux1394-devel@lists.sourceforge.net, jarod@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next] firewire: net: really fix maximum possible MTU From: David Miller In-Reply-To: <20161029221658.03942ff6@kant> References: <20161023162903.4166a35d@kant> <20161023163056.6bc38610@kant> <20161029221658.03942ff6@kant> X-Mailer: Mew version 6.7 on Emacs 25.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sat, 29 Oct 2016 19:01:31 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 732 Lines: 16 From: Stefan Richter Date: Sat, 29 Oct 2016 22:16:58 +0200 > The maximum unicast datagram size /without/ link fragmentation is > 4096 - 4 = 4092 (max IEEE 1394 async payload size at >= S800 bus speed, > minus unfragmented encapssulation header). Max broadcast datagram size > without fragmentation is 8 bytes less than that (due to GASP header). > > The maximum datagram size /with/ link fragmentation is 0xfff = 4095 > for unicast and broadcast. This is because the RFC 2734 fragment > encapsulation header field for datagram size is only 12 bits wide. > > Fixes: 5d48f00d836a('firewire: net: fix maximum possible MTU') > Signed-off-by: Stefan Richter Applied, thanks.