Re: [PATCH net-next v2] net: Add fib rules at vrf device create

[David Miller <davem@davemloft.net>]

From: David Ahern <dsa@cumulusnetworks.com>
Date: Tue,  8 Dec 2015 12:48:05 -0800

> VRFs require ip rules for route lookups to work properly. Currently
> creating a VRF means instantiating a device and then adding the 4 ip
> and ip6 rules:
> 
>     ip link add vrf-${VRF} type vrf table ${TBID}
>     ip ru add oif vrf-${VRF} table ${TBID}
>     ip ru add iif vrf-${VRF} table ${TBID}
>     ip -6 ru add oif vrf-${VRF} table $TBID
>     ip -6 ru add iif vrf-${VRF} table $TBID
> 
> Since the table is required when the vrf device is created the rules can
> be inserted automatically lightening the overhead and improving the
> user experience (only the ip link add is needed).
> 
> Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
> ---
> v2
> - addressed comments from Nik

Unfortunately it's too late for this, you should have considered this
issue fully when VRF first went into an upstream release.

If I add your change, the user experience is _worse_.

Users on older kernels have to use the full sequence, then if they
upgrade their kernels to one with this patch then the 'ru add' et
al. commands will fail.