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Date:   Wed, 26 Jun 2019 19:28:29 -0700 (PDT)
Message-Id: <20190626.192829.1694521513812984310.davem@davemloft.net>
To:     yuehaibing@huawei.com
Cc:     sdf@google.com, jianbol@mellanox.com, jiri@mellanox.com,
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        netdev@vger.kernel.org
Subject: Re: [PATCH v2] flow_dissector: Fix vlan header offset in
 __skb_flow_dissect
From:   David Miller <davem@davemloft.net>
In-Reply-To: <20190624034913.40328-1-yuehaibing@huawei.com>
References: <20190622.161955.2030310177158651781.davem@davemloft.net>
        <20190624034913.40328-1-yuehaibing@huawei.com>
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From: YueHaibing <yuehaibing@huawei.com>
Date: Mon, 24 Jun 2019 11:49:13 +0800

> @@ -998,6 +998,9 @@ bool __skb_flow_dissect(const struct net *net,
>  		    skb && skb_vlan_tag_present(skb)) {
>  			proto = skb->protocol;
>  		} else {
> +			if (dissector_vlan == FLOW_DISSECTOR_KEY_MAX)
> +				nhoff -= sizeof(*vlan);
> +

But this is wrong when we are being called via eth_get_headlen(), in
that case nhoff will be sizeof(struct ethhdr).