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From: "Timo Teräs" <timo.teras@iki•fi>
To: Herbert Xu <herbert@gondor•apana.org.au>
Cc: netdev@vger•kernel.org
Subject: Re: [PATCH] xfrm: cache bundle lookup results in flow cache
Date: Wed, 17 Mar 2010 18:32:53 +0200	[thread overview]
Message-ID: <4BA10435.9050300@iki.fi> (raw)
In-Reply-To: <4BA0FBB6.10208@iki.fi>

Timo Teräs wrote:
>>> Also. With this and your recent flowi patch, I'm seeing pmtu
>>> issues. Seems like xfrm_bundle_ok uses the original dst which
>>> resulted in the creation of the bundle. Somehow that dst
>>> does not get updated with pmtu... but the new dst used in
>>> next xfrm_lookup for same target does have proper mtu.
>>> I'm debugging right now why this is happening. Any ideas?
>>
>> The dynamic MTU is always maintained in a normal dst object in
>> the IPv4 routing cache.  Each xfrm_dst points to such a dst
>> through xdst->route.
>>
>> If you were looking at the xfrm_dst's own MTU then that may well
>> cause problems.
> 
> I figured the root cause. The original dst gets expired
> rt_genid goes old. But xfrm_dst does not notice that so it
> won't create a new bundle. xfrm_bundle_ok calls dst_check,
> but dst->obsolete = 0, and ipv4_dst_check is a no-op anyway.
> 
> Somehow the rtable object should be able to tell back to
> xfrm that the dst is not good anymore. Any ideas?

Checked ipv6, it does like xfrm: sets obsolote to -1 and
on dst_check checks the genid. We need to do same in for
ipv4. I just wrote an hack, and tested it. It solves the
pmtu issues.

I will post a proper patch soon.

- Timo

  reply	other threads:[~2010-03-17 16:32 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-15 12:20 [PATCH] xfrm: cache bundle lookup results in flow cache Timo Teras
2010-03-17 13:07 ` Herbert Xu
2010-03-17 14:16   ` Timo Teräs
2010-03-17 14:58     ` Herbert Xu
2010-03-17 15:56       ` Timo Teräs
2010-03-17 16:32         ` Timo Teräs [this message]
2010-03-18 19:30         ` Timo Teräs
2010-03-19  0:31           ` Herbert Xu
2010-03-19  5:48             ` Timo Teräs
2010-03-19  6:03               ` Herbert Xu
2010-03-19  6:21                 ` Timo Teräs
2010-03-19  7:17                   ` Herbert Xu
2010-03-19  7:27                   ` Timo Teräs
2010-03-19  0:32           ` Herbert Xu
2010-03-19  7:20 ` Herbert Xu
2010-03-19  7:48   ` Timo Teräs
2010-03-19  8:29     ` Herbert Xu
2010-03-19  8:37       ` Timo Teräs
2010-03-19  8:47         ` Herbert Xu
2010-03-19  9:12           ` Timo Teräs
2010-03-19  9:32             ` Herbert Xu
2010-03-19  9:53               ` Timo Teräs
2010-03-20 15:17                 ` Herbert Xu
2010-03-20 16:26                   ` Timo Teräs
2010-03-21  0:46                     ` Herbert Xu
2010-03-21  7:34                       ` Timo Teräs
2010-03-21  8:31                         ` Timo Teräs
2010-03-22  3:52                           ` Herbert Xu
2010-03-22 18:03                             ` Timo Teräs
2010-03-23  7:28                               ` Timo Teräs
2010-03-23  7:42                                 ` Herbert Xu
2010-03-23  9:19                                   ` Timo Teräs
2010-03-23  9:41                                     ` Herbert Xu
2010-03-22  1:26                   ` David Miller
2010-03-22  1:28                   ` David Miller
2010-03-22  1:32                     ` Herbert Xu
2010-03-22  1:36                       ` David Miller
2010-03-22  1:40                         ` Herbert Xu
2010-03-22  3:12                           ` David Miller
2010-03-22  3:52                             ` Herbert Xu
2010-03-22 18:31                               ` Timo Teräs

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