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 <[email protected]> > --- > 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 <[email protected]> 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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
