Re: CVS commit: src/sys/netinet

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

On Fri, Apr 6, 2018 at 7:04 PM, Roy Marples <roy%marples.name@localhost> wrote:
> On 06/04/2018 10:19, Ryota Ozaki wrote:
>>
>> Module Name:    src
>> Committed By:   ozaki-r
>> Date:           Fri Apr  6 09:19:16 UTC 2018
>>
>> Modified Files:
>>         src/sys/netinet: in.c
>>
>> Log Message:
>> Simplify; clear then set flags to ia4_flags (NFCI)
>
>
> This change is not right.
> You are clearing the flags for an already existing address and now allows
> this:
>
> ifconfig bge0 1.2.3.4/16
> address becomes tentative
> ifconfig bge0 1.2.3.4/16
> address flags cleared, address can be used before DaD finishes.
>
> Can we match it to the inet6 path and at least remember if existing flags
> were TENTATIVE | DETACHED? That is only done there because we can update
> flags from userland, we have no mechanism for this in inet hence the slight
> difference.
>
> I would also be happier with always setting DETACHED on link down, but only
> setting TENTATIVE if ip_dad_count > 0.
> Would that help solve your issue with GARP? What is GARP anyway?

Not enough. GARP wasn't sent because of the check in arpannounce:

        if (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED)) {
                ARPLOG(LOG_DEBUG, "%s not ready\n", ARPLOGADDR(ip));
                return;
        }
        arprequest(ifp, ip, ip, enaddr);

So my change was to not set any flags if !(ip_dad_count > 0).
Do you have another idea to avoid the situation?

Nonetheless, I don't expect breaking ip_dad_count > 0 case, so I'll
restore it anyway.

Thanks,
  ozaki-r