Re: [PATCH RFC net-next 07/20] net/ipv6: Move nexthop data to fib6_nh

[Wei Wang <weiwan@google.com>]

On Mon, Feb 26, 2018 at 2:47 PM, David Ahern <dsahern@gmail.com> wrote:
> On 2/26/18 3:28 PM, Wei Wang wrote:
>> On Sun, Feb 25, 2018 at 11:47 AM, David Ahern <dsahern@gmail.com> wrote:
>>> Introduce fib6_nh structure and move nexthop related data from
>>> rt6_info and rt6_info.dst to fib6_nh. References to dev, gateway or
>>> lwtstate from a FIB lookup perspective are converted to use fib6_nh;
>>> datapath references to dst version are left as is.
>>>
>>
>> My understanding is that after your whole patch series, sibling routes
>> will still have their own fib6_info. Does it make sense to make this
>> fib6_nh as an array in fib6_info so that sibling routes will share
>> fib6_info but will have their own fib6_nh as a future improvement? It
>> matches ipv4 behavior. And I think it will make the sibling route
>> handling code easier?
>
> I was not planning to. IPv6 allowing individual nexthops to be added and
> deleted is very convenient. I do agree the existing sibling route
> linkage makes the code much more complicated than it needs to be.
>
> After this set, I plan to send patches for nexthops as separate objects
> - which will have an impact on how multipath routes are done. With
> nexthop objects there will be 1 prefix route pointing to a nexthop
> object that is multipath (meaning it points in turn to a series of
> nexthop objects). This provides the simplification (no sibling linkage)
> without losing the individual nexhtop add / delete option.

Got it. Thanks for the explanation.