http://git.kernel.org/?p=linux/kernel/git/davem/net-next-2.6.git;a=commitdiff;h=3b885787ea4112eaa80945999ea0901bf742707f
This is done by using recvmsg() instead of recvfrom() to allow the timestamp
and the dropcounter to be received within one syscall.
When the application (here 'candump') ist not fast enough to process the
incomming CAN frames the frames are dropped in the socket receive queue.
When this happens and '-d' is set, we get this info now:
DROPCOUNT: dropped 1 CAN frame on 'xxx' socket (total drops 1)
Due to a wrong safety check in af_can.c it was not possible to filter
for SFF frames with a specific CAN identifier without getting the
same selected CAN identifier from a received EFF frame also.
This fix has a minimum impact on the CAN filter API as the 'sloppy'
handling is still a correct (and possibly wanted?) use-case.
Please update the can-utils (especially candump) whose filter definition
on the commandline made assumptions to correct the user input that are
probably unwanted now.
Thanks to Kurt van Dijck for pointing at this issue!
Signed-Off-by: Oliver Hartkopp <oliver@hartkopp.net>
Most SocketCAN userspace tools (like cansend) recognize the EFF by the
stringlength of the given CAN-ID: 3 -> SFF , 8 -> EFF.
This was missing in the candump filter definition and therefore the
values had to be specified with the CAN_EFF_FLAG set in the value, e.g.
92345678 for the extended CAN-ID 12345678 - this was not really nice.
Now the filtersets for extended frames can be specified as expected:
12345678:1FFFFFFF to filter for only 12345678 extended CAN-ID
000000AA:1FFFFFFF to filter for only AA extended CAN-ID.
Now you can forward CAN frames e.g. via netcat with candump and canplayer:
candump can0 can1 -L | canplayer vcan3=can0 vcan0=can1 -t
OK, maybe it would be reasonable to write a short program for this application.
But for some tests all this can be done with existing commandline tools.
In addition the filtering possibilities of candump can be used here.
Added new tool 'canplayer' to replay logfiles generated by candump -l .
Features of canplayer:
- Input from stdin or file.
- throttling of the replay to get nearly original timestamps / message gaps
- mapping and selection of CAN interfaces (assignment)
e.g. canplay -I logfile vcan2=can2 vcan0=can1 can2=can3
means: send frames received on can1 in the logfile to vcan0 and so on ...
- if no assignment is made the original interfaces are used for replay
- handling of multiple CAN interfaces simultaneously (if in logfile)
- option: throttle disable (do not look on timestamps => very FAST replay!)
- option: change the 'sleep time' in milli seconds
Remarks:
canplayer uses nanosleep() for throttling which means that the resolution of
the canplayer is about 1ms (Kernel HZ = 1000) or 10ms (Kernel HZ = 100).
After each nanosleep() all the CAN frames are send that had to be transmitted
until the timestamp at the current time. Giving e.g. the option '-g 500' for
500ms let's you see the behaviour. Using nanosleep() makes canplay a very
performant tool with minimum CPU load.
To transfer CAN frames over a TCP/IP network you may now say something like:
candump -> netcat -> netcat -> canplayer
- added sprint_* functions for CAN-frame output in lib.c / lib.h
- added comments / cosmetics
candump.c:
- removed support for the output in ASC representation (moved to log2asc.c)
- added option '-l' for logfile creation e.g. 'candump-2007-01-01_164123.log'
- added funtionality to terminate candump by pressing [ENTER] (not only ^C)
- added error frame support
- added color support even when reading from 'any'
- three different color levels (e.g. -c -c -c)
- making use if lib.c
cangen.c:
- CAN frames generator for testing purposes (e.g. on vcanx)
(nice when you're on vacancy at the baltic sea and have no real CAN source :)
log2long.c:
- convert compact CAN frame representation into user readable representation
log2asc.c:
- convert compact CAN frame logfile to ASC logfile for 3rd party CAN tools
Next step: Create a tool to replay candump logfiles.
Move version.h to include/linux/can.
Fix Makefiles to include raw.ko and bcm.ko in compilation and to make
vcan compile again.
Change ioctl names in SJA1000 driver to make it compile again.
Add parenthesis around assignment in vcan.c to eliminate gcc warning.
Oliver Hartkopp
Urs Thuermann