netdev - Re: [PATCH v2] openvswitch: Trim off padding before L3+ netfilter processing

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Date:   Fri, 5 Jan 2018 22:17:26 -0800
From:   Pravin Shelar <pshelar@....org>
To:     Ed Swierk <eswierk@...portsystems.com>
Cc:     ovs-dev <ovs-dev@...nvswitch.org>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>,
        Benjamin Warren <ben@...portsystems.com>,
        Keith Holleman <holleman@...portsystems.com>
Subject: Re: [PATCH v2] openvswitch: Trim off padding before L3+ netfilter processing

On Fri, Jan 5, 2018 at 3:20 PM, Ed Swierk <eswierk@...portsystems.com> wrote:
> On Fri, Jan 5, 2018 at 10:14 AM, Ed Swierk <eswierk@...portsystems.com>
> wrote:
>> On Thu, Jan 4, 2018 at 7:36 PM, Pravin Shelar <pshelar@....org> wrote:
>>> OVS already pull all required headers in skb linear data, so no need
>>> to redo all of it. only check required is the ip-checksum validation.
>>> I think we could avoid it in most of cases by checking skb length to
>>> ipheader length before verifying the ip header-checksum.
>>
>> Shouldn't the IP header checksum be verified even earlier, like in
>> key_extract(), before actually using any of the fields in the IP
>> header?
>
> Something like this for verifying the IP header checksum (not tested):
>
AFAIU openflow does not need this verification, so it is not required
in flow extract.