netdev - Re: xfrm: UFO + ESP = double fragmentation

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Date:	Sat, 30 Jan 2016 12:21:02 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Jiri Bohac <jbohac@...e.cz>
Cc:	Steffen Klassert <steffen.klassert@...unet.com>,
	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: xfrm: UFO + ESP = double fragmentation

On Sat, Jan 30, 2016 at 12:44:24AM +0100, Jiri Bohac wrote:
>
> Is there a situation when xfrm_output_gso() does the right thing?

Yes because you've just broken TSO over IPsec.

In fact you're remarkably close to the right solution which is
to avoid xfrm_output_gso for SKB_GSO_UDP packets.

You should also work through all the other types (e.g., tunnels)
one-by-one and determine which ones should be fragmented and
which ones shouldn't.

Cheers,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt