netdev - Re: [PATCH/RFC net-next 0/4] net/sched: cls_flower: avoid false matching of truncated packets

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Message-ID: <2c14754a-f3f5-cece-2cd7-361948a00c22@mojatatu.com>
Date:   Fri, 28 Apr 2017 09:41:00 -0400
From:   Jamal Hadi Salim <jhs@...atatu.com>
To:     Simon Horman <simon.horman@...ronome.com>
Cc:     Jiri Pirko <jiri@...lanox.com>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Dinan Gunawardena <dinan.gunawardena@...ronome.com>,
        netdev@...r.kernel.org, oss-drivers@...ronome.com
Subject: Re: [PATCH/RFC net-next 0/4] net/sched: cls_flower: avoid false
 matching of truncated packets

On 17-04-28 09:11 AM, Simon Horman wrote:
> On Fri, Apr 28, 2017 at 08:52:56AM -0400, Jamal Hadi Salim wrote:
>> On 17-04-28 08:00 AM, Simon Horman wrote:
>>> Hi,
>>>
>>> this series is intended to avoid false-positives which match
>>> truncated packets against flower classifiers which match on:
>>> * zero L4 ports or;
>
> How would you describe such a rule? The case that is being dealt with is
> one where there is a parse error and thus nothing to match on from a flower
> pov.
>

A default lower prio match all on udp or icmp?

>> Example what would offloading of
>> header_parse_err_action mean?
>
> Why would it need to differ semantically to the implementation in this
> patch? I feel that I am missing something.
>

Unless I misunderstood:
Isnt the issue the dissector that confused something missing L4 ports
and said "port is zero"?

Unless the hardware has the same "bug" as the dissector seems like would
be a different semantic in the h/ware.

cheers,
jamal