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From: Jiri Benc <jbenc@redhat.com>
To: Pravin Shelar <pshelar@ovn.org>
Cc: Jarno Rajahalme <jarno@ovn.org>,
	Linux Kernel Network Developers <netdev@vger.kernel.org>,
	Eric Garver <e@erig.me>
Subject: Re: [PATCH v3 net-next 2/3] openvswitch: Use is_skb_forwardable() for length check.
Date: Fri, 2 Dec 2016 10:25:09 +0100	[thread overview]
Message-ID: <20161202102509.065df1e8@griffin> (raw)
In-Reply-To: <CAOrHB_BEQBbvDa2W0dJmmANsjZEiwx7GbTxo-7yirDB=5d9cqQ@mail.gmail.com>

On Thu, 1 Dec 2016 11:50:00 -0800, Pravin Shelar wrote:
> This is not changing any behavior compared to current OVS vlan checks.
> Single vlan header is not considered for MTU check.

It is changing it.

Consider the case when there's an interface with MTU 1500 forwarding to
an interface with MTU 1496. Obviously, full-sized vlan frames
ingressing on the first interface are not forwardable to the second
one. Yet, if the vlan tag is accelerated (and thus not counted in
skb->len), is_skb_forwardable happily returns true because of the check

        len = dev->mtu + dev->hard_header_len + VLAN_HLEN;
        if (skb->len <= len)

 Jiri

  reply	other threads:[~2016-12-02  9:25 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-29 23:30 [PATCH v3 net-next 1/3] openvswitch: Add a missing break statement Jarno Rajahalme
2016-11-29 23:30 ` [PATCH v3 net-next 2/3] openvswitch: Use is_skb_forwardable() for length check Jarno Rajahalme
2016-11-30  7:23   ` Pravin Shelar
2016-11-30 13:51   ` Jiri Benc
2016-11-30 21:30     ` Jarno Rajahalme
2016-12-01 19:50     ` Pravin Shelar
2016-12-02  9:25       ` Jiri Benc [this message]
2016-12-05  0:22         ` Pravin Shelar
2016-12-08 20:50           ` Eric Garver
2016-12-09  8:49             ` Jiri Benc
2016-11-29 23:30 ` [PATCH v3 net-next 3/3] openvswitch: Fix skb->protocol for vlan frames Jarno Rajahalme
2016-11-30  7:34   ` Pravin Shelar
2016-11-30 14:30   ` Jiri Benc
2016-12-01 20:31     ` Pravin Shelar
2016-12-02  9:42       ` Jiri Benc
2016-12-02  9:49         ` Jiri Benc
2016-12-05  0:58         ` Pravin Shelar
2016-12-14  5:07 ` [PATCH v3 net-next 1/3] openvswitch: Add a missing break statement Pravin Shelar
2016-12-20  1:07   ` Jarno Rajahalme

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