Subject: Re: [PATCH net-next 07/13] ipv6: Move gateway checks to a fib6_nh setting

From: Ido Schimmel <[email-masked]>
Date: Wed, 27 Mar 2019 09:08:02 +0000

On Tue, Mar 26, 2019 at 08:29:36PM -0700, David Ahern wrote:
> @@ -989,8 +989,11 @@ static void ip6_rt_copy_init(struct rt6_info *rt, struct fib6_info *ort)
>  
>  	rt->rt6i_dst = ort->fib6_dst;
>  	rt->rt6i_idev = dev ? in6_dev_get(dev) : NULL;
> -	rt->rt6i_gateway = ort->fib6_nh.nh_gw;
>  	rt->rt6i_flags = ort->fib6_flags;
> +	if (ort->fib6_nh.fib_nh_has_gw) {
> +		rt->rt6i_gateway = ort->fib6_nh.nh_gw;
> +		rt->rt6i_flags |= RTF_GATEWAY;

Not sure I understand why this line is needed. Can you explain?

> +	}
>  	rt6_set_from(rt, ort);
>  #ifdef CONFIG_IPV6_SUBTREES
>  	rt->rt6i_src = ort->fib6_src;
> @@ -1870,7 +1873,7 @@ struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,

...

> @@ -3134,7 +3138,7 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
>  	} else
>  		rt->fib6_prefsrc.plen = 0;
>  
> -	rt->fib6_flags = cfg->fc_flags;
> +	rt->fib6_flags = cfg->fc_flags & ~RTF_GATEWAY;

This is going to break mlxsw. See:

mlxsw_sp_fib6_rt_can_mp()
mlxsw_sp_rt6_is_gateway()

>  
>  	return rt;
>  out:
> @@ -3470,7 +3474,8 @@ static struct fib6_info *rt6_get_route_info(struct net *net,