From: shengyong <shengyong1@huawei•com>
To: Steffen Klassert <steffen.klassert@secunet•com>
Cc: <davem@davemloft•net>, <netdev@vger•kernel.org>,
<yangyingliang@huawei•com>, <hannes@redhat•com>
Subject: Re: Question: should local address be expired when updating PMTU?
Date: Fri, 27 Feb 2015 10:37:46 +0800 [thread overview]
Message-ID: <54EFD87A.5080907@huawei.com> (raw)
In-Reply-To: <20150205072125.GY13046@secunet.com>
在 2015/2/5 15:21, Steffen Klassert 写道:
> On Wed, Feb 04, 2015 at 09:59:54AM +0800, shengyong wrote:
>>
>> Sorry, the later. I test it on 3.10-stable. It can fix this problem. So maybe this is a bug?
>
> Yes, it's a bug.
>
>> And the 3 approaches (different flags are used: RTF_LOCAL, IFF_LOOPBACK and RTF_CACHE) in
>> these mails can fix the expire of local address. I'm confused about these flags:
>> * RTF_LOCAL: the entries of local address, like address binded to the native NIC
>> * RTF_CACHE: all cached entries
>> * IFF_LOOPBACK: this is a device-related flag, which has the same meaning as RTF_LOCAL
>>
>> Am I right? If so, I think RTF_LOCAL is appropriate, because we just want entries of local
>> addresses to be not expired and we don't care other entries (I think if they get expired,
>> a neigh discovery could find them back).
>
> It is not the address that expires, it is the learned PMTU value that
> expires. If we delete an uncached route, nothing will bring it back
> unless you readd it manually.
>
> We need to ensure that all routes that can learn something what
> expires are cached. This means that we clone the inserted route
> when it is used for the first time. The learned values are stored
> at this cloned route. If the learned value expires, the clone is
> deleted. The original route remains in the fib tree and can be
> still looked up.
>
> The problem is, that we currently don't cache/clone host routes.
> So if a host route learns something that expires, the original
> route is removed from the fib tree and we loose connectivity
> to that host. We don't cache host routes because some of them
> (the local ones) are automatically added with metric 0.
> If we try to cache such a route, the clone will be identical
> to the original route and we fail to insert it to the fib tree.
>
> So we need to adjust the caching to all routes that actually can
> learn something and leave out only those that can not.
>
> I'll send a patchset that should fix this at the beginning of the
> next week.
Hi, Steffen
Is this patchset ready? It seems that I didn't find it in the mainling
list. If it is ready, I can test it to see if it solves the problem I
met :)
many thanks,
Sheng
>
> .
>
next prev parent reply other threads:[~2015-02-27 2:38 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-02 8:20 Question: should local address be expired when updating PMTU? shengyong
2015-02-02 21:31 ` David Miller
2015-02-03 0:52 ` Alex Gartrell
2015-02-03 1:28 ` shengyong
2015-02-03 2:10 ` Calvin Owens
2015-02-03 3:21 ` shengyong
2015-02-03 9:28 ` Steffen Klassert
2015-02-03 10:54 ` shengyong
2015-02-03 12:01 ` Steffen Klassert
2015-02-04 1:59 ` shengyong
2015-02-05 7:21 ` Steffen Klassert
2015-02-27 2:37 ` shengyong [this message]
2015-02-27 10:32 ` Steffen Klassert
2015-03-30 10:32 ` Steffen Klassert
2015-03-30 10:33 ` [PATCH RFC 1/3] ipv6: Fix after pmtu events dissapearing host routes Steffen Klassert
2015-03-30 11:15 ` Sheng Yong
2015-03-30 18:24 ` Martin Lau
2015-04-01 8:09 ` Steffen Klassert
2015-03-30 10:33 ` [PATCH RFC 2/3] ipv6: Extend the route lookups to low priority metrics Steffen Klassert
2015-03-30 10:34 ` [PATCH RFC 3/3] ipv6: Don't update pmtu on uncached routes Steffen Klassert
2015-03-30 11:13 ` Question: should local address be expired when updating PMTU? Sheng Yong
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