From: Gao feng <gaofeng@cn•fujitsu.com>
To: RongQing Li <roy.qing.li@gmail•com>,
netdev@vger•kernel.org,
Hannes Frederic Sowa <hannes@stressinduktion•org>
Subject: Re: [PATCH] ipv6: clear RTF_EXPIRES when call ip6_rt_copy
Date: Tue, 17 Dec 2013 15:46:24 +0800 [thread overview]
Message-ID: <52B00150.3070002@cn.fujitsu.com> (raw)
In-Reply-To: <20131217070231.GA11970@order.stressinduktion.org>
On 12/17/2013 03:02 PM, Hannes Frederic Sowa wrote:
> On Tue, Dec 17, 2013 at 02:42:01PM +0800, RongQing Li wrote:
>> 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?
>
> Good question. ;)
>
> I wonder, too. In the past from and expires were a union and either from or
> expires was allowed to be used. In the commit you referred to this union was
> split into seperate fields.
>
> It somehow worked in the past because routes normally have longer timeouts
> and the routes will get evicted from the route cache eventually. My guess
> is that we can set from unconditionally or copy over the expires value.
>
> This patch already needed quite a long time to review for me and I am still
> unsure. :/
>
> Gao, do you still remember why you used RTF_ADDRCONF|RTF_DEFAULT?
>
It's a mystery， I noticed this problem when I wrote the codes.
http://lists.openwall.net/netdev/2012/03/19/7
I used the flags RTF_ADDRCONF|RTF_DEFAULT because they are exist in
rt6_{get,add,purge}_dflt_router.
The from of new cloned rt should not be set if it's impossible for the ort
to be expired.
but seems we should set from if flags have RTF_ADDRCONF bit. RA package
not only generate the default route.
next prev parent reply other threads:[~2013-12-17 7:46 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-16 8:31 [PATCH] ipv6: clear RTF_EXPIRES when call ip6_rt_copy roy.qing.li
2013-12-16 13:47 ` Eric Dumazet
2013-12-17 3:25 ` Gao feng
2013-12-17 3:32 ` RongQing Li
2013-12-17 5:57 ` Gao feng
2013-12-17 6:42 ` RongQing Li
2013-12-17 7:02 ` Hannes Frederic Sowa
2013-12-17 7:46 ` Gao feng [this message]
2013-12-17 8:30 ` Hannes Frederic Sowa
2013-12-17 9:23 ` Gao feng
2013-12-17 13:48 ` Hannes Frederic Sowa
2013-12-18 0:48 ` Gao feng
2013-12-18 1:58 ` RongQing Li
2013-12-18 2:09 ` Gao feng
2013-12-18 2:21 ` RongQing Li
2013-12-18 6:20 ` Hannes Frederic Sowa
2013-12-18 8:40 ` Gao feng
2013-12-19 0:37 ` Hannes Frederic Sowa
2013-12-19 0:47 ` RongQing Li
2013-12-19 4:40 ` [PATCH v2] ipv6: always set the new created dst's from in ip6_rt_copy roy.qing.li
2013-12-19 12:43 ` Hannes Frederic Sowa
2013-12-19 23:36 ` David Miller
2013-12-18 7:59 ` [PATCH] ipv6: clear RTF_EXPIRES when call ip6_rt_copy Hannes Frederic Sowa
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