Subject: Re: [patch net-next 14/17] mlxsw: spectrum_router: Add support for IPv6 routes addition / deletion

From: Ido Schimmel <[email-masked]>
Date: Wed, 19 Jul 2017 19:43:45 +0300

On Wed, Jul 19, 2017 at 10:36:52AM -0600, David Ahern wrote:
> >> 2. How are routes with devices unrelated to ports owned by this driver
> >> handled?
> > 
> > They are handled just like any other route, but they don't have a valid
> > RIF (for directly connected routes) or an adjacency group (for
> > gatewayed routes), so the check in mlxsw_sp_fib_entry_should_offload()
> > will return false and they will be programmed to the device with trap
> > action, but using a trap ID (RTR_INGRESS0) with a lower traffic class
> > than IP2ME, so packets that actually need to be locally received by the
> > CPU have a better QoS.
> 
> so mlxsw keeps a copy of the complete FIB for IPv4 and IPv6, even routes
> unrelated to its ports?

If we don't reflect all the routes in the system to the ASIC, then we'll
have a broken routing table and a different behavior from what you would
get with plain NICs.