Re: RFC: nexthop cache separation

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

On Wed, Mar 23, 2016 at 12:31 AM, David Young <dyoung%pobox.com@localhost> wrote:
> On Tue, Mar 22, 2016 at 01:14:39PM +0900, Ryota Ozaki wrote:
>> Hi,
>>
>> Here are new patches:
>>   http://www.netbsd.org/~ozaki-r/separate-nexthop-caches-v2.diff
>>   http://www.netbsd.org/~ozaki-r/separate-nexthop-caches-v2-diff.diff
>>
>> Changes since v1:
>> - Comment out osbolete RTF_* and RTM_* definitions
>>   - Tweak some userland codes for the change
>> - Restore checks of connected (cloning) routes in nd6_is_addr_neighbor
>> - Restore the original behavior on removing ARP/NDP entries for
>>   IP addresses of interface itself
>> - Remove remaining use of RTF_LLINFO in the kernel
>>   - I think we can remove it safely
>
> It sounds as if these changes could affect the appearance of netstat -r,
> route show, route get, arp -a, arp <hostname>.  Can you provide some
> before/after examples?

The following outputs (from ATF test t_arp:cache_expiration_10s)
are differences between them. netstat -r and route show should
be almost the same output (because they're sharing a common code),
and arp -a and arp <hostname> should not be different basically
(just output one or all).

The differences of the former (what I figure out) are:
- No nexthop cache entries exist
- A route of interfaces's IP address doesn't have MAC address;
  its gateway is a sockaddr of AF_LINK w/o address
and the latter shouldn't change.

I don't have examples of route get outputs now. I'll provide
them later. (I think we need some tests for it.)

========================================
[before]
tc-so:Routing tables
tc-so:
tc-so:Internet:
tc-so:Destination        Gateway            Flags    Refs      Use
Mtu Interface
tc-so:10.0.1/24          link#2             UC          -        -
 -  shmif0
tc-so:10.0.1.1           b2:a0:03:c7:32:39  UHLc        -        -
 -  shmif0
tc-so:10.0.1.2           b2:a0:ff:e2:30:fd  UHLl        -        -      -  lo0
tc-so:127.0.0.1          lo0                UHl         -        -  33648  lo0

tc-so:? (10.0.1.1) at b2:a0:03:c7:32:39 on shmif0
tc-so:? (10.0.1.2) at b2:a0:ff:e2:30:fd on shmif0 permanent

[after]
tc-so:Routing tables
tc-so:
tc-so:Internet:
tc-so:Destination        Gateway            Flags    Refs      Use
Mtu Interface
tc-so:10.0.1/24          link#2             UC          -        -
 -  shmif0
tc-so:10.0.1.2           link#2             UHl         -        -      -  lo0
tc-so:127.0.0.1          lo0                UHl         -        -  33648  lo0

tc-so:? (10.0.1.2) at b2:a0:cb:56:b5:52 on shmif0 permanent
tc-so:? (10.0.1.1) at b2:a0:fd:ce:b5:21 on shmif0
========================================

  ozaki-r