From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hannes Frederic Sowa Subject: Re: [PATCH ipsec 1/3] ipv6: wire up skb->encapsulation Date: Sat, 17 Aug 2013 20:07:38 +0200 Message-ID: <20130817180738.GA24518@order.stressinduktion.org> References: <20130817175116.GA7001@order.stressinduktion.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: netdev@vger.kernel.org, steffen.klassert@secunet.com, yoshfuji@linux-ipv6.org, nicolas.dichtel@6wind.com To: horms@verge.net.au Return-path: Received: from order.stressinduktion.org ([87.106.68.36]:57944 "EHLO order.stressinduktion.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754006Ab3HQSHj (ORCPT ); Sat, 17 Aug 2013 14:07:39 -0400 Content-Disposition: inline In-Reply-To: <20130817175116.GA7001@order.stressinduktion.org> Sender: netdev-owner@vger.kernel.org List-ID: Hi Simon! On Sat, Aug 17, 2013 at 07:51:16PM +0200, Hannes Frederic Sowa wrote: > When pushing a new header before current one call skb_reset_inner_headers > to record the position of the inner headers in the various ipv6 tunnel > protocols. > > We later need this to correctly identify the addresses needed to send > back an error in the xfrm layer. > > This change is safe, because skb->protocol is always checked before > dereferencing data from the inner protocol. > > Cc: Steffen Klassert > Cc: YOSHIFUJI Hideaki > Cc: Nicolas Dichtel > Signed-off-by: Hannes Frederic Sowa > --- > > This patch is based on Steffen Klassert's ipsec tree. > > net/ipv6/ip6_gre.c | 5 +++++ > net/ipv6/ip6_tunnel.c | 6 ++++++ > net/ipv6/sit.c | 5 +++++ > 3 files changed, 16 insertions(+) > > diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c > index ecd6073..90747f1 100644 > --- a/net/ipv6/ip6_gre.c > +++ b/net/ipv6/ip6_gre.c > @@ -724,6 +724,11 @@ static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb, > ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL); > } > > + if (likely(!skb->encapsulation)) { > + skb_reset_inner_headers(skb); > + skb->encapsulation = 1; > + } > + While doing these patches, I wondered how skb->inner_protocol will be used in future (you added it in 0d89d2035fe063461a5ddb609b2c12e7fb006e44 ("MPLS: Add limited GSO support")). Current use by tunnels seems safe to me, but I wondered how you would extend its use? Thanks, Hannes