linux.git/include/uapi/linux/can.h, branch v6.6.132

can: uapi: move CAN_RAW_FILTER_MAX definition to raw.h

2023-06-22T07:44:28+00:00

CAN_RAW_FILTER_MAX is only relevant for CAN_RAW sockets and used in
linux/can/raw.c or in userspace applications that include the raw.h
file anyway.

Signed-off-by: Oliver Hartkopp 
Link: https://lore.kernel.org/all/20230609121051.9631-1-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde

can: canxl: introduce CAN XL data structure

2022-09-15T07:08:09+00:00

This patch adds defines for data structures and length information for
CAN XL (CAN with eXtended data Length) which can transfer up to 2048
byte inside a single frame.

Notable changes from CAN FD:

- the 11 bit arbitration field is now named 'priority' instead of 'can_id'
  (there are no 29 bit identifiers nor RTR frames anymore)
- the data length needs a uint16 value to cover up to 2048 byte
  (the length element position is different to struct can[fd]_frame)
- new fields (SDT, AF) and a SEC bit have been introduced
- the virtual CAN interface identifier is not part if the CAN XL frame
  struct as this VCID value is stored in struct skbuff (analog to vlan id)

Acked-by: Vincent Mailhol 
Signed-off-by: Oliver Hartkopp 
Link: https://lore.kernel.org/all/20220912170725.120748-5-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde

can: set CANFD_FDF flag in all CAN FD frame structures

2022-09-15T07:08:08+00:00

To simplify the testing in user space all struct canfd_frame's provided by
the CAN subsystem of the Linux kernel now have the CANFD_FDF flag set in
canfd_frame::flags.

NB: Handcrafted ETH_P_CANFD frames introduced via PF_PACKET socket might
not set this bit correctly. During the check for sufficient headroom in
PF_PACKET sk_buffs the uninitialized CAN sk_buff data structures are filled.
In the case of a CAN FD frame the CANFD_FDF flag is set accordingly.

As the CAN frame content is already zero initialized in alloc_canfd_skb()
the obsolete initialization of cf->flags in the CTU CAN FD driver has been
removed as it would overwrite the already set CANFD_FDF flag.

Acked-by: Vincent Mailhol 
Signed-off-by: Oliver Hartkopp 
Link: https://lore.kernel.org/all/20220912170725.120748-4-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde

can: uapi: introduce CANFD_FDF flag for mixed content in struct canfd_frame

2021-05-27T07:42:21+00:00

The struct can_frame and struct canfd_frame intentionally share the
same layout to be able to write CAN frame content into a CAN FD frame
structure. When this is done the former differentiation via CAN_MTU /
CANFD_MTU is lost. CANFD_FDF allows programmers to mark CAN FD frames
in the case of using struct canfd_frame for mixed CAN/CAN FD
content (dual use).

N.B. the Kernel APIs do NOT provide mixed CAN / CAN FD content inside
of struct canfd_frame therefore the CANFD_FDF flag is disregarded by
Linux.

Link: https://lore.kernel.org/r/20170411134343.3089-1-socketcan@hartkopp.net
Signed-off-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: uapi: update CAN-FD frame description

2021-05-27T07:42:21+00:00

Since an early version of the CAN-FD specification the bit that
defines a CAN-FD frame on the wire, has been renamed from Extended
Data Length (EDL) to FD Frame (FDF).

To avoid confusion, update the struct canfd_frame description in the
UAPI headers accordingly.

Link: https://lore.kernel.org/r/20210517113727.77597-1-mkl@pengutronix.de
Suggested-by: Ayoub Kaanich 
Acked-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: uapi: can.h: mark union inside struct can_frame packed

2021-03-29T07:51:49+00:00

In commit ea7800565a12 ("can: add optional DLC element to Classical
CAN frame structure") the struct can_frame::can_dlc was put into an
anonymous union with another u8 variable.

For various reasons some members in struct can_frame and canfd_frame
including the first 8 byes of data are expected to have the same
memory layout. This is enforced by a BUILD_BUG_ON check in af_can.c.

Since the above mentioned commit this check fails on ARM kernels
compiled with the ARM OABI (which means CONFIG_AEABI not set). In this
case -mabi=apcs-gnu is passed to the compiler, which leads to a
structure size boundary of 32, instead of 8 compared to CONFIG_AEABI
enabled. This means the the union in struct can_frame takes 4 bytes
instead of the expected 1.

Rong Chen illustrates the problem with pahole in the ARM OABI case:

| struct can_frame {
|          canid_t                    can_id;               /* 0     4 */
|          union {
|                  __u8               len;                  /* 4     1 */
|                  __u8               can_dlc;              /* 4     1 */
|          };                                               /* 4     4 */
|          __u8                       __pad;                /* 8     1 */
|          __u8                       __res0;               /* 9     1 */
|          __u8                       len8_dlc;             /* 10    1 */
|
|          /* XXX 5 bytes hole, try to pack */
|
|          __u8                       data[8]
| __attribute__((__aligned__(8))); /*    16     8 */
|
|          /* size: 24, cachelines: 1, members: 6 */
|          /* sum members: 19, holes: 1, sum holes: 5 */
|          /* forced alignments: 1, forced holes: 1, sum forced holes: 5 */
|          /* last cacheline: 24 bytes */
| } __attribute__((__aligned__(8)));

Marking the anonymous union as __attribute__((packed)) fixes the
BUILD_BUG_ON problem on these compilers.

Fixes: ea7800565a12 ("can: add optional DLC element to Classical CAN frame structure")
Reported-by: kernel test robot 
Suggested-by: Rong Chen 
Link: https://lore.kernel.org/linux-can/2c82ec23-3551-61b5-1bd8-178c3407ee83@hartkopp.net/
Link: https://lore.kernel.org/r/20210325125850.1620-3-socketcan@hartkopp.net
Signed-off-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: add optional DLC element to Classical CAN frame structure

2020-11-20T08:43:29+00:00

ISO 11898-1 Chapter 8.4.2.3 defines a 4 bit data length code (DLC) table which
maps the DLC to the payload length of the CAN frame in bytes:

    DLC      ->  payload length
    0 .. 8   ->  0 .. 8
    9 .. 15  ->  8

Although the DLC values 8 .. 15 in Classical CAN always result in a payload
length of 8 bytes these DLC values are transparently transmitted on the CAN
bus. As the struct can_frame only provides a 'len' element (formerly 'can_dlc')
which contains the plain payload length ( 0 .. 8 ) of the CAN frame, the raw
DLC is not visible to the application programmer, e.g. for testing use-cases.

To access the raw DLC values 9 .. 15 the len8_dlc element is introduced, which
is only valid when the payload length 'len' is 8 and the DLC is greater than 8.

The len8_dlc element is filled by the CAN interface driver and used for CAN
frame creation by the CAN driver when the CAN_CTRLMODE_CC_LEN8_DLC flag is
supported by the driver and enabled via netlink configuration interface.

Reported-by: Vincent Mailhol 
Signed-off-by: Oliver Hartkopp 
Link: https://lore.kernel.org/r/20201110101852.1973-2-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde

can: don't use deprecated license identifiers

2019-11-05T11:44:34+00:00

The "GPL-2.0" license identifier changed to "GPL-2.0-only" in SPDX v3.0.

Signed-off-by: Yegor Yefremov 
Acked-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: extend sockaddr_can to include j1939 members

2019-09-04T11:29:15+00:00

This patch prepares struct sockaddr_can for SAE J1939.

Signed-off-by: Kurt Van Dijck 
Signed-off-by: Oleksij Rempel 
Acked-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde

can: add socket type for CAN_J1939

2019-09-04T11:29:15+00:00

This patch is a preparation for SAE J1939 and adds CAN_J1939
socket type.

Signed-off-by: Kurt Van Dijck 
Signed-off-by: Oleksij Rempel 
Acked-by: Oliver Hartkopp 
Signed-off-by: Marc Kleine-Budde