Re: [PATCH] ipv6: clear RTF_EXPIRES when call ip6_rt_copy

[RongQing Li <roy.qing.li@gmail.com>]

On 12/17/13, Gao feng <gaofeng@cn.fujitsu.com> wrote:
> On 12/17/2013 11:32 AM, RongQing Li wrote:
>> If the ort->rt6i_flags is RTF_EXPIRES|RTF_ADDRCONF, then rt6_set_from will
>> not
>> be called, and new created rt will have RTF_EXPIRES, but dst.expires is 0,
>> and
>> dst.from is NULL
>
> Ok, but I think you need to add more detail/test purpose of the test case
> v6LC.4.1.4
> { Reduce PMTU On-link }. just the number of test case is not good for people
> to know
> what's the real problem.
>

I have a question, why does we set dst.from only when the ort has flag
RTF_ADDRCONF
and RTF_DEFAULT?

-Roy


>>
>> -Roy
>>
>> 2013/12/17 Gao feng <gaofeng@cn.fujitsu.com>:
>>> On 12/16/2013 04:31 PM, roy.qing.li@gmail.com wrote:
>>>> From: Li RongQing <roy.qing.li@gmail.com>
>>>>
>>>> The commit ecd9883724b [ipv6: fix race condition regarding dst->expires
>>>> and
>>>> dst->from.] removed rt6_clean_expires in ip6_rt_copy, which causes the
>>>> TAHI
>>>> test case v6LC.4.1.4 { Reduce PMTU On-link } failed, since the newly
>>>> generated
>>>> rt maybe always expired {with RTF_EXPIRES flag, dst.expires is 0, and
>>>> dst.from
>>>> is NULL}.
>>>>
>>>> Fix it by clearing RTF_EXPIRES as before 1716a96101[ipv6: fix problem
>>>> with
>>>> expired dst cache]
>>>>
>>>> Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
>>>> ---
>>>>  net/ipv6/route.c |    2 +-
>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
>>>> index a1a5752..e3d7f21 100644
>>>> --- a/net/ipv6/route.c
>>>> +++ b/net/ipv6/route.c
>>>> @@ -1908,7 +1908,7 @@ static struct rt6_info *ip6_rt_copy(struct
>>>> rt6_info *ort,
>>>>                       rt->rt6i_gateway = ort->rt6i_gateway;
>>>>               else
>>>>                       rt->rt6i_gateway = *dest;
>>>> -             rt->rt6i_flags = ort->rt6i_flags;
>>>> +             rt->rt6i_flags = ort->rt6i_flags & ~RTF_EXPIRES;
>>>>               if ((ort->rt6i_flags & (RTF_DEFAULT | RTF_ADDRCONF)) ==
>>>>                   (RTF_DEFAULT | RTF_ADDRCONF))
>>>>                       rt6_set_from(rt, ort);
>>>>
>>>
>>> I don't understand, rt6_set_from already clears the RTF_EXPIRES from
>>> rt->rt6i_flags.
>>>
>>
>
>