On Mon. 21 Aug. 2023 at 04:21, Oliver Hartkopp <socketcan@xxxxxxxxxxxx> wrote: > On 19.08.23 15:29, Vincent Mailhol wrote: > > On Sat. 19 Aug. 2023 at 22:10, Vincent Mailhol > > <vincent.mailhol@xxxxxxxxx> wrote: > >> On Sat. 19 Aug. 2023, 01:19, Jakub Kicinski <kuba@xxxxxxxxxx> wrote: > >>> > >>> On Thu, 17 Aug 2023 12:10:13 +0200 Martin Hundebøll wrote: > >>>> + int len = nla_len(data[IFLA_CAN_HW_FILTER]); > >>>> + int num_filter = len / sizeof(struct can_filter); > >>>> + struct can_filter *filter = nla_data(data[IFLA_CAN_HW_FILTER]); > >>> > >>> This will prevent you from ever extending struct can_filter in > >>> a backward-compatible fashion, right? I obviously know very little > >>> about CAN but are you confident a more bespoke API to manipulate > >>> filters individually and allow extensibility is not warranted? > >> > >> I follow Jakub's point of view. > >> > >> The current struct can_filter is not sound. Some devices such as the > >> ES582.1 supports filtering of the CAN frame based on the flags (i.e. > >> SFF/EFF, RTR, FDF). > > > > I wrote too fast. The EFF and RTR flags are contained in the canid_t, > > so the current struct can_filter is able to handle these two flags. > > But it remains true that the CAN-FD flags (FDF and BRS) are currently > > not handled. Not to mention that more flags will come with the > > upcoming CAN XL. > > You are right with FDF where we could use the former CAN_ERR_FLAG value > which is not needed for hw filter API. And what about the BRS flag? > But regarding CAN XL we could use the Standard 11 bit ID handling with > another flag inside the remaining 18 bits. Then, wouldn't you still need one more flag to indicate that this is a CAN XL filter? > The general concept of re-using the struct can_filter makes sense to me > as this follows the widely used pattern in the af_can.c core and CAN_RAW > sockets. > > Best regards, > Oliver > > > > >> I think that each of the fields of the filter should have its own NLA > >> declaration with the whole thing wrapped within a NLA_NESTED_ARRAY. > >> > >> I also think that there should then be a method to report the precise > >> filtering capabilities of the hardware. > >> > >> > >> Yours sincerely, > >> Vincent Mailhol
