From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladislav Yasevich Subject: [PATCH 1/2] vlan: Fix untag operations of stacked vlans with REORDER_HEADER off Date: Mon, 16 Nov 2015 15:43:44 -0500 Message-ID: <1447706625-25979-2-git-send-email-vyasevic@redhat.com> References: <1447706625-25979-1-git-send-email-vyasevic@redhat.com> Cc: phil@nwl.cc, kaber@trash.net, Vladislav Yasevich To: netdev@vger.kernel.org Return-path: Received: from mail-qg0-f48.google.com ([209.85.192.48]:32876 "EHLO mail-qg0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751041AbbKPUnz (ORCPT ); Mon, 16 Nov 2015 15:43:55 -0500 Received: by qgea14 with SMTP id a14so58328869qge.0 for ; Mon, 16 Nov 2015 12:43:54 -0800 (PST) In-Reply-To: <1447706625-25979-1-git-send-email-vyasevic@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: When we have multiple stacked vlan devices all of which have turned off REORDER_HEADER flag, the untag operation does not locate the ethernet addresses correctly for nested vlans. The reason is that in case of REORDER_HEADER flag being off, the outer vlan headers are put back and the mac_len is adjusted to account for the presense of the header. Then, the subsequent untag operation, for the next level vlan, always use VLAN_ETH_HLEN to locate the begining of the ethernet header and that ends up being a multiple of 4 bytes short of the actuall beginning of the mac header (the multiple depending on the how many vlan encapsulations ethere are). As a reslult, if there are multiple levles of vlan devices with REODER_HEADER being off, the recevied packets end up being dropped. To solve this, we use skb->mac_len as the offset. The value is always set on receive path and starts out as a ETH_HLEN. The value is also updated when the vlan header manupations occur so we know it will be correct. Signed-off-by: Vladislav Yasevich --- net/core/skbuff.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index fab4599..160193f 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -4268,7 +4268,8 @@ static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb) return NULL; } - memmove(skb->data - ETH_HLEN, skb->data - VLAN_ETH_HLEN, 2 * ETH_ALEN); + memmove(skb->data - ETH_HLEN, skb->data - skb->mac_len, + 2 * ETH_ALEN); skb->mac_header += VLAN_HLEN; return skb; } -- 1.9.3