Re: [PATCH] can: add new socket option CAN_RAW_FILTER_UNIQUE to eliminate duplicate matches

[Oliver Hartkopp <socketcan@hartkopp.net>]

On 17.03.2015 16:36, Andre Naujoks wrote:
> On 17.03.2015 13:58, Oliver Hartkopp wrote:
>> The CAN_RAW socket can set multiple CAN identifier specific filters that lead
>> to multiple filters in the af_can.c filter processing. These filters are
>> indenpendent from each other which leads to logical OR'ed filters when applied.
>>
>> Especially when the filter is intended to notch single CAN IDs or CAN ID ranges
>> a problem emerges when using more than just one filter: The notched CAN IDs
>> will be delivered once while the other CAN IDs will be delivered twice.
>>
>> This patch implements a new option to make sure that every CAN frame which is
>> filtered for a specific socket is only delivered once to the user space.
>> This is independent from the number of matching CAN filters of this socket.
>
> Hi Oliver.
>
> I don't think this should be an option. A CAN-frame should never be
> delivered more than once even if multiple filters match.
>
> In my eyes this is a long standing bug ;-), which would get an
> off-switch this way.

https://www.youtube.com/watch?v=4JgxDxwf7RU

:-))

So you think the 'unifying option' should be enabled by default!?!
Would you assume this to break any user space apps?

Btw. what's your opinion about

http://marc.info/?l=linux-can&m=142660595731528&w=2

??

Regards,
Oliver