Re: [PATCH v2] net: sysctl for RA default route MTU

[Hannes Frederic Sowa <hannes@stressinduktion.org>]

On Wed, Mar 25, 2015, at 12:07, Roman Gushchin wrote:
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -1714,6 +1714,14 @@ int ip6_route_add(struct fib6_config *cfg)
>  
>  	rt->rt6i_flags = cfg->fc_flags;
>  
> +       if ((cfg->fc_flags & (RTF_ADDRCONF | RTF_DEFAULT | RTF_GATEWAY))
> ==
> +           (RTF_ADDRCONF | RTF_DEFAULT | RTF_GATEWAY)) {
> +               u32 mtu = idev->cnf.ra_default_route_mtu;
> +
> +               if (mtu && mtu >= IPV6_MIN_MTU && mtu <= idev->cnf.mtu6)
> +                       dst_metric_set(&rt->dst, RTAX_MTU, mtu);
> +       }
> +

Could you move this RA specific snippet over to ndisc.c?

Hmm

How do you use this option?

You use jumbo frames on the on-link network and announce all routes via
route options where you also want to communicate to with jumbo frames?

I wonder if an offlink_mtu parameter would be more suitable?

Thanks,
Hannes