Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754599Ab3JDNc1 (ORCPT ); Fri, 4 Oct 2013 09:32:27 -0400 Received: from order.stressinduktion.org ([87.106.68.36]:40634 "EHLO order.stressinduktion.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752754Ab3JDNcZ (ORCPT ); Fri, 4 Oct 2013 09:32:25 -0400 Date: Fri, 4 Oct 2013 15:32:23 +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: [PATCHv2] IPv6: Allow the MTU of ipip6 tunnel to be set below 1280 Message-ID: <20131004133223.GA11410@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: <1380808166-13280-1-git-send-email-ou.ghorbel@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1380808166-13280-1-git-send-email-ou.ghorbel@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1857 Lines: 52 On Thu, Oct 03, 2013 at 02:49:26PM +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 | 12 ++++++++++-- > 1 file changed, 10 insertions(+), 2 deletions(-) > > diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c > index 46ba243..4b51b03 100644 > --- a/net/ipv6/ip6_tunnel.c > +++ b/net/ipv6/ip6_tunnel.c > @@ -1429,9 +1429,17 @@ 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 *tnl = netdev_priv(dev); > + > + if (tnl->parms.proto == IPPROTO_IPIP) { > + if (new_mtu < 68) > + return -EINVAL; > + } else { > + if (new_mtu < IPV6_MIN_MTU) > + return -EINVAL; > } > + if (new_mtu > 0xFFF8 - dev->hard_header_len) > + return -EINVAL; > dev->mtu = new_mtu; > return 0; > } Acked-by: Hannes Frederic Sowa Anytime soon we should replace all the FFF8 with a symbolic constant. 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/