Re: Make sure to insert ifa/ia after initialization

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

On Wed, Jun 29, 2016 at 3:22 AM, Roy Marples <roy%marples.name@localhost> wrote:
> On 2016-06-28 02:03, Ryota Ozaki wrote:
>>
>> Hi,
>>
>> Basically we should insert an item to a collection
>> (say a list) after completed item's initialization to
>> avoid accessing an item that is initialized halfway.
>>
>> ifaddr and in{,6}_ifaddr aren't processed like so.
>> The patch below fixes the issue.
>>
>>   http://www.netbsd.org/~ozaki-r/insert_ifa_after_init.diff
>>
>> To this end, I need to tweak {arp,nd6}_rtrequest that
>> depend on that an ifaddr (in{,6}_ifaddr) is inserted
>> during its initialization; they explore interface's
>> address list to determine that rt_getkey(rt) of a given
>> rtentry is in the list (i.e., whether the route's
>> interface should be a loopback), which doesn't work
>> after the change. To make it work I use RTF_LOCAL flag
>> instead.
>>
>> Any comments or suggestions?
>
>
> +               if (rt->rt_flags & RTF_LOCAL) {
> +                       rt->rt_expire = 0;
> +                       if (useloopback) {
> +                               rt->rt_ifp = lo0ifp;
> +                               rt->rt_rmx.rmx_mtu = 0;
> +                       }
>                 }
> -               rt->rt_flags |= RTF_LOCAL;
> -               /*
>
> This has reverted r1.181 which had this comment:
> If, for whatever reason, a local interface route is removed and then
> re-added, mark it as a local route.

Thank you for pointing it out! I think we can restore the behavior
by restoring the removed code that should work for the case because
the address already exists in the list. (Updated the patch.)

>
> You've tested manually removing and re-adding the local route and noticing
> the flag is preserved?

I'm trying, but I don't know how to re-add. Could you tell me how
to do that?

  kvm# ifconfig vioif0 10.0.0.1/24
  kvm# netstat -nr -f inet |grep 10.0.0.1
  10.0.0.1           link#1             UHLl        -        -      -  lo0
  kvm# route delete 10.0.0.1
  delete host 10.0.0.1
  kvm# netstat -nr -f inet |grep 10.0.0.1
  kvm# route add -host 10.0.0.1 -iface vioif0
  route: vioif0: bad value
  kvm# route add -host 10.0.0.1 -iface lo0
  route: lo0: bad value

Thanks,
  ozaki-r