[ovs-dev] [PATCH V3 14/40] ip_gre: remove the incorrect mtu limit for ipgre tap

William Tu u9012063 at gmail.com
Mon May 21 22:07:47 UTC 2018


On Fri, May 18, 2018 at 5:49 PM, Greg Rose <gvrose8192 at gmail.com> wrote:
> From: Xin Long <lucien.xin at gmail.com>
>
> Upstream commit:
>     commit cfddd4c33c254954927942599d299b3865743146
>     Author: Xin Long <lucien.xin at gmail.com>
>     Date:   Mon Dec 18 14:24:35 2017 +0800
>
>     ip_gre: remove the incorrect mtu limit for ipgre tap
>
>     ipgre tap driver calls ether_setup(), after commit 61e84623ace3
>     ("net: centralize net_device min/max MTU checking"), the range
>     of mtu is [min_mtu, max_mtu], which is [68, 1500] by default.
>
>     It causes the dev mtu of the ipgre tap device to not be greater
>     than 1500, this limit value is not correct for ipgre tap device.
>
>     Besides, it's .change_mtu already does the right check. So this
>     patch is just to set max_mtu as 0, and leave the check to it's
>     .change_mtu.
>
>     Fixes: 61e84623ace3 ("net: centralize net_device min/max MTU checking")
>     Reported-by: Jianlin Shi <jishi at redhat.com>
>     Signed-off-by: Xin Long <lucien.xin at gmail.com>
>     Signed-off-by: David S. Miller <davem at davemloft.net>
>
> Cc: Xin Long <lucien.xin at gmail.com>
> Signed-off-by: Greg Rose <gvrose8192 at gmail.com>
> ---

Acked-by: William Tu <u9012063 at gmail.com>

>  datapath/linux/compat/ip_gre.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/datapath/linux/compat/ip_gre.c b/datapath/linux/compat/ip_gre.c
> index 028586c..f849971 100644
> --- a/datapath/linux/compat/ip_gre.c
> +++ b/datapath/linux/compat/ip_gre.c
> @@ -367,6 +367,7 @@ static int gre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *unused_tpi)
>         if (unlikely(tpi.proto == htons(ETH_P_ERSPAN))) {
>                 if (erspan_rcv(skb, &tpi, hdr_len) == PACKET_RCVD)
>                         return 0;
> +               goto drop;

nit: I think this is another patch from Xin Long.

>         }
>
>         if (ipgre_rcv(skb, &tpi, hdr_len) == PACKET_RCVD)
> @@ -390,7 +391,6 @@ static int gre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *__tpi)
>
>         if (ipgre_rcv(skb, &tpi, 0) == PACKET_RCVD)
>                 return 0;
> -
>  drop:
>
>         kfree_skb(skb);
> @@ -1182,6 +1182,7 @@ static void ipgre_tunnel_setup(struct net_device *dev)
>  static void ipgre_tap_setup(struct net_device *dev)
>  {
>         ether_setup(dev);
> +       dev->max_mtu = 0;
>         dev->netdev_ops         = &gre_tap_netdev_ops;
>         dev->priv_flags         |= IFF_LIVE_ADDR_CHANGE;
>         ip_tunnel_setup(dev, gre_tap_net_id);
> --
> 1.8.3.1
>
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