Re: [PATCH net-next] ipmr: ip6mr: Add ability to display non default caches and vifs

[Nikolay Aleksandrov <nikolay@nvidia.com>]

On 18/08/2021 23:09, Stephen Suryaputra wrote:
> With multiple mroute tables it seems that there should be a way to
> display caches and vifs for the non-default table. Add two sysctls to
> control what to display. The default values for the sysctls are
> RT_TABLE_DEFAULT (253) and RT6_TABLE_DFLT (254).
> 
> Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
> ---
>  Documentation/networking/ip-sysctl.rst | 14 ++++++++++++++
>  include/net/netns/ipv4.h               |  3 +++
>  include/net/netns/ipv6.h               |  3 +++
>  net/ipv4/af_inet.c                     |  3 +++
>  net/ipv4/ipmr.c                        | 14 ++++++++++++--
>  net/ipv4/sysctl_net_ipv4.c             |  9 +++++++++
>  net/ipv6/ip6mr.c                       | 14 ++++++++++++--
>  net/ipv6/route.c                       |  3 +++
>  net/ipv6/sysctl_net_ipv6.c             |  9 +++++++++
>  9 files changed, 68 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
> index d91ab28718d4..de47563514f0 100644
> --- a/Documentation/networking/ip-sysctl.rst
> +++ b/Documentation/networking/ip-sysctl.rst
> @@ -1382,6 +1382,13 @@ mc_forwarding - BOOLEAN
>  	conf/all/mc_forwarding must also be set to TRUE to enable multicast
>  	routing	for the interface

Sorry, but I don't see any point to this. We don't have it for any of the other
non-default cases, and I don't see a point of having it for ipmr either.
If you'd like to display the non-default tables then you query for them, you
don't change a sysctl to see them in /proc.
It sounds like a workaround for an issue that is not solved properly, and
generally it shouldn't be using /proc. If netlink interfaces are not sufficient
please improve them.

Why do we need a whole new sysctl or net proc entries ?

Cheers,
 Nik