From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17175C43613 for ; Thu, 20 Jun 2019 10:02:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E9DD32147A for ; Thu, 20 Jun 2019 10:02:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731484AbfFTKCm (ORCPT ); Thu, 20 Jun 2019 06:02:42 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:18644 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726268AbfFTKCm (ORCPT ); Thu, 20 Jun 2019 06:02:42 -0400 Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 201F6524BC4FF94BC2CB; Thu, 20 Jun 2019 18:02:39 +0800 (CST) Received: from [127.0.0.1] (10.133.213.239) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.439.0; Thu, 20 Jun 2019 18:02:35 +0800 Subject: Re: [PATCH] flow_dissector: Fix vlan header offset in __skb_flow_dissect To: Stanislav Fomichev References: <20190619160132.38416-1-yuehaibing@huawei.com> <20190619183938.GA19111@mini-arch> CC: , , , , , , , From: Yuehaibing Message-ID: <00a5d09f-a23e-661f-60c0-75fba6227451@huawei.com> Date: Thu, 20 Jun 2019 18:02:34 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20190619183938.GA19111@mini-arch> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.133.213.239] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/6/20 2:39, Stanislav Fomichev wrote: > On 06/20, YueHaibing wrote: >> We build vlan on top of bonding interface, which vlan offload >> is off, bond mode is 802.3ad (LACP) and xmit_hash_policy is >> BOND_XMIT_POLICY_ENCAP34. >> >> __skb_flow_dissect() fails to get information from protocol headers >> encapsulated within vlan, because 'nhoff' is points to IP header, >> so bond hashing is based on layer 2 info, which fails to distribute >> packets across slaves. >> >> Fixes: d5709f7ab776 ("flow_dissector: For stripped vlan, get vlan info from skb->vlan_tci") >> Signed-off-by: YueHaibing >> --- >> net/core/flow_dissector.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c >> index 415b95f..2a52abb 100644 >> --- a/net/core/flow_dissector.c >> +++ b/net/core/flow_dissector.c >> @@ -785,6 +785,9 @@ bool __skb_flow_dissect(const struct sk_buff *skb, >> skb && skb_vlan_tag_present(skb)) { >> proto = skb->protocol; >> } else { >> + if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX) >> + nhoff -= sizeof(*vlan); >> + > Should we instead fix the place where the skb is allocated to properly > pull vlan (skb_vlan_untag)? I'm not sure this particular place is > supposed to work with an skb. Having an skb with nhoff pointing to > IP header but missing skb_vlan_tag_present() when with > proto==ETH_P_8021xx seems weird. The skb is a forwarded vxlan packet, it send through vlan interface like this: vlan_dev_hard_start_xmit --> __vlan_hwaccel_put_tag //vlan_tci and VLAN_TAG_PRESENT is set --> dev_queue_xmit --> validate_xmit_skb --> validate_xmit_vlan // vlan_hw_offload_capable is false --> __vlan_hwaccel_push_inside //here skb_push vlan_hlen, then clear skb->tci --> bond_start_xmit --> bond_xmit_hash --> __skb_flow_dissect // nhoff point to IP header --> case htons(ETH_P_8021Q) // skb_vlan_tag_present is false, so vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), //vlan point to ip header wrongly > >> vlan = __skb_header_pointer(skb, nhoff, sizeof(_vlan), >> data, hlen, &_vlan); >> if (!vlan) { >> -- >> 2.7.0 >> >> > > . >