From: Steffen Klassert <steffen.klassert@secunet.com>
To: Jiri Bohac <jbohac@suse.cz>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
"David S. Miller" <davem@davemloft.net>, <netdev@vger.kernel.org>
Subject: Re: [PATCH] xfrm: don't segment UFO packets
Date: Thu, 17 Mar 2016 12:01:31 +0100 [thread overview]
Message-ID: <20160317110131.GH3347@gauss.secunet.com> (raw)
In-Reply-To: <20160317104953.GB11706@midget.suse.cz>
On Thu, Mar 17, 2016 at 11:49:53AM +0100, Jiri Bohac wrote:
> On Thu, Mar 17, 2016 at 11:24:59AM +0100, Steffen Klassert wrote:
> > > > On Wed, Mar 16, 2016 at 05:00:26PM +0100, Jiri Bohac wrote:
> > > Fixes my broken case.
> >
> > Is this IPv4 or IPv6? IPv4 should not create a GSO skb
> > if IPsec is done. It checks for rt->dst.header_len
> > in __ip_append_data() and does a fallback to the
> > standard case if rt->dst.header_len is non zero.
>
> It's IPv6.
>
> > In IPv6 this check is missing, so this could be the
> > problem if this is IPv6.
>
> Doesn't the check do exactly the opposite of what the RFC says?
> The RFC wants ESP to be performed first and fragmentation after
> that. UDPv4 currently seems to be doing the opposite.
No, __ip_append_data() only prepares the packets for fragmentation
and enqueues them. Then __ip_make_skb() dequeues and builds
one skb with a fraglist. Then the xfrm layer is called, so
esp linearizes (unfortunately) the skb and applies the
transformation. Fragmentation happens after that.
next prev parent reply other threads:[~2016-03-17 11:01 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-29 23:44 xfrm: UFO + ESP = double fragmentation Jiri Bohac
2016-01-30 4:21 ` Herbert Xu
2016-03-16 16:00 ` [PATCH] xfrm: don't segment UFO packets Jiri Bohac
2016-03-17 5:03 ` Herbert Xu
2016-03-17 9:41 ` Jiri Bohac
2016-03-17 10:24 ` Steffen Klassert
2016-03-17 10:49 ` Jiri Bohac
2016-03-17 11:01 ` Steffen Klassert [this message]
2016-03-17 17:08 ` Jiri Bohac
2016-03-18 2:36 ` Herbert Xu
2016-03-18 8:05 ` Steffen Klassert
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