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From: "Timo Teräs" <timo.teras@iki.fi>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Miller <davem@davemloft.net>,
	netdev@vger.kernel.org, kuznet@ms2.inr.ac.ru
Subject: Re: ip_gre headroom allocation
Date: Thu, 11 Jun 2009 14:29:46 +0300	[thread overview]
Message-ID: <4A30EAAA.4070907@iki.fi> (raw)
In-Reply-To: <20090611105638.GA2085@gondor.apana.org.au>

Herbert Xu wrote:
> On Thu, Jun 11, 2009 at 01:17:14PM +0300, Timo Teräs wrote:
>>> Otherwise we'd need a similar hack in ipip.c too.
>> I was under the impression that as we need to do the route lookup anyway
>> we could take advantage of the information available from there fully.
>>
>> But yes, your explanation makes perfect sense.
> 
> I think you're both right :)
> 
> We should include the IPsec head room here, but also in the
> dev->needed_headroom calculation so that most packets don't
> get reallocated in the first place.

I guess this is easy for point-to-point tunnels. But how about the
multipoint gre tunnels? The needed_headroom can vary on destination
basis depending on if they are NATted or not, and on the cipher/hash
used.

Can we change the needed_headroom on-the-fly? Increase it when ever
we encounter a larger path? But this also means some packages would
get extra headroom allocated.

- Timo


  reply	other threads:[~2009-06-11 11:29 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-11  8:22 ip_gre headroom allocation Timo Teräs
2009-06-11 10:09 ` David Miller
2009-06-11 10:17   ` Timo Teräs
2009-06-11 10:56     ` Herbert Xu
2009-06-11 11:29       ` Timo Teräs [this message]
2009-06-11 11:37         ` Herbert Xu
2009-06-11 11:51           ` Timo Teräs
2009-06-11 12:12             ` Herbert Xu

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