Whole CAN code in RIOT is using 'struct can_frame' to represent a CAN
frame.
However incoming CAN FD support will bring 'struct canfd_frame' to
represent CAN FD frames.
Even if the 'struct canfd_frame' has additional flags and a bigger
payload, it is aligned on 'struct can_frame' and thus they can be
referenced by the same pointers in the code.
As it is impossible to predict which one will be used in RIOT, just
define a new type 'can_frame_t' which will map to the right struct
according to the MCU CAN supported format.
Signed-off-by: Gilles DOFFE <gilles.doffe@rtone.fr>
Most functions were using asserts, but in some cases it might not be a
programmatic error to pass an invalid ifnum. This makes sure the code
does not crash by testing it at runtim and returning an error.
The CAN stack support only raw CAN at this time.
It contains a device interface (drivers/include/can/candev.h) and the data link
layer, build around can/device.c can/pkt.c and can/router.c. can/dll.c contains
the upper level and lower level interface to send and receive CAN frames.
Upper layer interface is located in include/can/raw.h
