Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753281Ab3I0Ihe (ORCPT ); Fri, 27 Sep 2013 04:37:34 -0400 Received: from order.stressinduktion.org ([87.106.68.36]:54641 "EHLO order.stressinduktion.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751548Ab3I0Ihb (ORCPT ); Fri, 27 Sep 2013 04:37:31 -0400 Date: Fri, 27 Sep 2013 10:37:30 +0200 From: Hannes Frederic Sowa To: Oussama Ghorbel Cc: "David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] IPv6: Allow the MTU of ipip6 tunnel to be set below 1280 Message-ID: <20130927083730.GC28287@order.stressinduktion.org> Mail-Followup-To: Oussama Ghorbel , "David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy , netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <1380207108-20030-1-git-send-email-oghorbell@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1380207108-20030-1-git-send-email-oghorbell@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1888 Lines: 53 On Thu, Sep 26, 2013 at 03:51:48PM +0100, Oussama Ghorbel wrote: > The (inner) MTU of a ipip6 (IPv4-in-IPv6) tunnel cannot be set below 1280, which is the minimum MTU in IPv6. > However, there should be no IPv6 on the tunnel interface at all, so the IPv6 rules should not apply. > More info at https://bugzilla.kernel.org/show_bug.cgi?id=15530 > > This patch allows to check the minimum MTU for ipv6 tunnel according to these rules: > -In case the tunnel is configured with ipip6 mode the minimum MTU is 68. > -In case the tunnel is configured with ip6ip6 or any mode the minimum MTU is 1280. > > Signed-off-by: Oussama Ghorbel > --- > net/ipv6/ip6_tunnel.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c > index 1e55866..a66ead2 100644 > --- a/net/ipv6/ip6_tunnel.c > +++ b/net/ipv6/ip6_tunnel.c > @@ -1423,8 +1423,14 @@ ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) > static int > ip6_tnl_change_mtu(struct net_device *dev, int new_mtu) > { > - if (new_mtu < IPV6_MIN_MTU) { > - return -EINVAL; > + struct ip6_tnl *t = netdev_priv(dev); > + > + if (t->parms.proto == IPPROTO_IPIP) { > + if (new_mtu < 68) > + return -EINVAL; Maybe you could have a look at ip_tunnel_change_mtu in ipv4/ip_tunnel.c, generalize this check as e.g. ip_tunnel_valid_mtu or something and use it here? Maybe an af-independent ip_tunnel_max_mtu()? > + } else { > + if (new_mtu < IPV6_MIN_MTU) > + return -EINVAL; This check could also be used here, then. > } > dev->mtu = new_mtu; > return 0; Thanks, Hannes -- 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/