Sebastian Smolorz wrote:
Hi Wolfgang,
we currently face an issue regarding the filtering of CAN messages since
Xenomai 2.4. It was introduced in rev. 2202 (I know it is long ago but
the problem popped up last week). The line in question is
http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/drivers/can/rtcan_raw_filter.c?v=2.3.5#064
and
http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/drivers/can/rtcan_raw_filter.c?v=2.4.4#062
respectively.
What worries me is the removal of the AND-operation (can_id can_mask).
From my POV this offends the CAN specification which says that the CAN
filter mask shall indicate which bits are taken into account when
comparing a CAN identifier and which shall be seen as don't care.
From your Changelog entry the reason for this modification was to be up
to date with the Linux Socket CAN project. So maybe there is also the
need to bring up this topic on their ML, too.
No, this looks like a Xenomai-exclusive bug. If I quick-read mainline
correctly, this line prevents that bits in can_id which should be
ignored according to the mask can cause problems when they are set:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=net/can/af_can.c;h=7d4d2b3c137ef6b84598d9bebd50b1a69dfaf707;hb=HEAD#l340
So, unless I'm now also misled, we are basically lacking a final
recv_filter-can_id = recv_filter-can_mask;
in rtcan_raw_mount_filter. Wolfgang, correct?
Jan
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