Re: RFC: nexthop cache separation

[Ryota Ozaki <ozaki-r%netbsd.org@localhost>]

On Tue, Apr 5, 2016 at 2:44 AM, David Young <dyoung%pobox.com@localhost> wrote:
> On Fri, Mar 25, 2016 at 07:41:18PM +0900, Ryota Ozaki wrote:
>> [after]
>> Routing tables
>>
>> Internet:
>> Destination        Gateway            Flags    Refs      Use
>> Mtu Interface
>> default            10.0.1.1           UGS         -        -
>>  -  shmif0
>> 10.0.1/24          link#2             UC          -        -
>>  -  shmif0
>> 10.0.1.2           link#2             UHl         -        -      -  lo0
>> 127.0.0.1          lo0                UHl         -        -  33648  lo0
>
> Previous to the change you've proposed, 'route show' provided a more
> comprehensive view of the routing state.  Now, it is missing several
> useful items.  Where has the 10.0.1.1 route gone?  Where are the
> MAC addresses?  Previously, you could issue one command and within
> an eyespan have all of the information that you needed to diagnose
> connectivity problems on routers.  Now, to first appearances, every
> routing state looks suspect, and it's necessary to dig in with arp/ndp
> to see if things are ok.

I think we can restore dropped information to route show output, but I'm
not sure whether they should be there while they're not L3 routes and we
can get them from arp/ndp commands easily. For the PoV of backward
compatibility, we should do so though...

>
> Please, if your changes materially change the user interface, provide
> mockups.  Mockups are powerful communication tools that help to build
> consensus and provide strong implementation guidance.  Design oversights
> that are obvious in mockups may be invisible in patches.  It's easy
> to mockup command-line displays like route(8)'s using $EDITOR.  I
> cannot recommend strongly enough that developers add mockups to their
> engineering-communications repertoire.

I think this should be done via ATF tests; they work like mockups and
also detect regressions with daily runs. Nonetheless, I didn't provide
enough tests for route show/netstat -r changes. That's my fault.

  ozaki-r