From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Duyck Subject: Looking for a lost patch Date: Wed, 13 May 2015 10:47:11 -0700 Message-ID: <55538E1F.2020505@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit To: steffen.klassert@secunet.com, David Miller , NetDev Return-path: Received: from mail-ie0-f174.google.com ([209.85.223.174]:35417 "EHLO mail-ie0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754636AbbEMRrN (ORCPT ); Wed, 13 May 2015 13:47:13 -0400 Received: by iebpz10 with SMTP id pz10so39234549ieb.2 for ; Wed, 13 May 2015 10:47:13 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: So I am in the process of trying to do some work on VTI6 and in the process of doing so I am trying to setup an IPv4 VTI tunnel and I have come across what appears to be a lost patch. So in commit a32452366b72 ("vti4: Don't count header length twice.") the following change was made: diff --git a/net/ipv4/ip_vti.c b/net/ipv4/ip_vti.c index 687ddef..cd62596 100644 --- a/net/ipv4/ip_vti.c +++ b/net/ipv4/ip_vti.c @@ -349,7 +349,6 @@ static int vti_tunnel_init(struct net_device *dev) memcpy(dev->broadcast, &iph->daddr, 4); dev->type = ARPHRD_TUNNEL; - dev->hard_header_len = LL_MAX_HEADER + sizeof(struct iphdr); dev->mtu = ETH_DATA_LEN; dev->flags = IFF_NOARP; dev->iflink = 0; However in commit f895f0cfbb77 ("Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec") the change appears to have been undone as a result of a merge commit. I'm just wondering which is correct. Should the hard_header_len be set or unset in vti_tunnel_init? I ask because I have two kernels and one has the patch and one does not and I am seeing an MTU of 1332 for a VTI tunnel without, and 1480 for a VTI tunnel with. - Alex