[ovs-dev] [PATCH] datapath: Bug fix: Missing mask attributes

Jesse Gross jesse at nicira.com
Fri Jun 21 17:12:35 UTC 2013


That sounds right to me.

On Fri, Jun 21, 2013 at 10:06 AM, Andy Zhou <azhou at nicira.com> wrote:
> You are right.
>
> The user space code needs to distinguish between two cases:
> 1) The entire mask attribute is missing, then the entire key is exact match.
> 2) The mask attribute is there, then the missing key attributes should be
> treated as wildcarded fields.
>
> It seems we don't need this patch, but make fixes to the user space program
> instead. What do you think?
>
>
> On Fri, Jun 21, 2013 at 9:55 AM, Jesse Gross <jesse at nicira.com> wrote:
>>
>> It doesn't really make sense that userspace would interpret a missing
>> attribute as exact match because when the flow is installed a missing
>> attribute means that it is wildcarded. Therefore, if you echoed back
>> the exact same flow it would have a different meaning.
>>
>> On Fri, Jun 21, 2013 at 9:43 AM, Andy Zhou <azhou at nicira.com> wrote:
>> > Correction.
>> >
>> > The ICMP mask will have to be fully masked in this example. But they
>> > still
>> > need to be present in the netlink. A missing ICMP mask attribute will be
>> > interpreted by the user space programs as exact match.
>> >
>> >
>> >
>> >
>> >
>> > On Fri, Jun 21, 2013 at 9:38 AM, Andy Zhou <azhou at nicira.com> wrote:
>> >>
>> >> Yes,  you are right about the root cause.
>> >>
>> >> A fully wildcarded ip proto in the key would prevent the mask of ICMP
>> >> (may
>> >> not be fully wildcarded) to be generated.
>> >> This patch fixes it.
>> >>
>> >> Andy
>> >>
>> >>
>> >> On Fri, Jun 21, 2013 at 9:27 AM, Jesse Gross <jesse at nicira.com> wrote:
>> >>>
>> >>> On Thu, Jun 20, 2013 at 11:38 PM, Andy Zhou <azhou at nicira.com> wrote:
>> >>> > Fix a bug where some mask attributes are missing in the netlink
>> >>> > packets
>> >>> > from kernel to the user space.
>> >>> >
>> >>> > Reported-by: Justin Pettit <jpettit at nicira.com>
>> >>> > Signed-off-by: Andy Zhou <azhou at nicira.com>
>> >>>
>> >>> Can you describe this some more? Presumably, this is because some of
>> >>> the prerequisite values are either fully or partially masked out and
>> >>> this is preventing latter masks from being emitted. However, since we
>> >>> force prerequisites to be exact match, doesn't that mean the omitted
>> >>> masks are fully wildcarded?
>> >>
>> >>
>> >
>
>



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