From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754120AbcAETth (ORCPT ); Tue, 5 Jan 2016 14:49:37 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:45668 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753999AbcAETtY (ORCPT ); Tue, 5 Jan 2016 14:49:24 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Vladislav Yasevich , "David S. Miller" , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 197/211] vlan: Fix untag operations of stacked vlans with REORDER_HEADER off Date: Tue, 5 Jan 2016 11:45:05 -0800 Message-Id: <1452023119-25647-198-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1452023119-25647-1-git-send-email-kamal@canonical.com> References: <1452023119-25647-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.2.8-ckt1 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Vlad Yasevich [ Upstream commit a6e18ff111701b4ff6947605bfbe9594ec42a6e8 ] 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 Signed-off-by: David S. Miller Signed-off-by: Kamal Mostafa --- 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 7bfa187..94c00af 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; } -- 1.9.1