From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarek Poplawski Subject: [PATCH] Re: problem with IPoA (CLIP), NAT, and VLANS Date: Tue, 17 Feb 2009 09:32:18 +0000 Message-ID: <20090217093218.GA5341@ff.dom.local> References: <20090216232016.GA4803@ami.dom.local> <499A7D7D.1090607@trash.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Karl Hiramoto , netdev@vger.kernel.org, netfilter@vger.kernel.org, LKML To: Patrick McHardy Return-path: Content-Disposition: inline In-Reply-To: <499A7D7D.1090607@trash.net> Sender: netfilter-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tue, Feb 17, 2009 at 10:03:57AM +0100, Patrick McHardy wrote: > Jarek Poplawski wrote: >> Very nice debugging, but I think your patch doesn't look like enough: >> 1) it skips copy for cloned skbs, >> 2) this skb_cow_head() is needed anyway, sometimes. >> So the real bug should be found in skb_cow_head() or elsewhere. >> >> I attach here 2 patches for testing: >> 1) skb->mac_header update: it looks like needed, but I don't know if >> it matters here, >> 2) an extention of your patch but with pskb_expand_head() called for >> one to one copy. >> >> BTW, if it's not a big problem it would be nice to try this e.g. on >> 2.6.29-rc5. > > The first patch looks fine. As for the second one, I would like > to understand why we're seing these packets. The VLAN driver uses > the original headroom plus the space it needs itself, which suggests > that the underlying driver specifies an incorrect headroom. > The driver doesn't appear to be part of the mainline kernel though. > The second patch is only for debugging: to check if it's about offset change or some values corrupted btw. Since the first patch looks quite natural I resend it for applying. I hope you'll ack it when Karl sends "Tested-by:" after checking it at least with the currently working (IPoE) vlan case. Thanks, Jarek P. -----------------> vlan: Update skb->mac_header in __vlan_put_tag(). After moving mac addresses in __vlan_put_tag() skb->mac_header() needs to be updated. Reported-by: Karl Hiramoto Signed-off-by: Jarek Poplawski --- include/linux/if_vlan.h | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h index f8ff918..e1ff5b1 100644 --- a/include/linux/if_vlan.h +++ b/include/linux/if_vlan.h @@ -210,6 +210,7 @@ static inline struct sk_buff *__vlan_put_tag(struct sk_buff *skb, u16 vlan_tci) /* Move the mac addresses to the beginning of the new header. */ memmove(skb->data, skb->data + VLAN_HLEN, 2 * VLAN_ETH_ALEN); + skb->mac_header -= VLAN_HLEN; /* first, the ethernet type */ veth->h_vlan_proto = htons(ETH_P_8021Q);