can: canxl: add virtual CAN network identifier support

CAN XL data frames contain an 8-bit virtual CAN network identifier (VCID).
A VCID value of zero represents an 'untagged' CAN XL frame.

To receive and send these optional VCIDs via CAN_RAW sockets a new socket
option CAN_RAW_XL_VCID_OPTS is introduced to define/access VCID content:

- tx: set the outgoing VCID value by the kernel (one fixed 8-bit value)
- tx: pass through VCID values from the user space (e.g. for traffic replay)
- rx: apply VCID receive filter (value/mask) to be passed to the user space

With the 'tx pass through' option CAN_RAW_XL_VCID_TX_PASS all valid VCID
values can be sent, e.g. to replay full qualified CAN XL traffic.

The VCID value provided for the CAN_RAW_XL_VCID_TX_SET option will
override the VCID value in the struct canxl_frame.prio defined for
CAN_RAW_XL_VCID_TX_PASS when both flags are set.

With a rx_vcid_mask of zero all possible VCID values (0x00 - 0xFF) are
passed to the user space when the CAN_RAW_XL_VCID_RX_FILTER flag is set.
Without this flag only untagged CAN XL frames (VCID = 0x00) are delivered
to the user space (default).

The 8-bit VCID is stored inside the CAN XL prio element (only in CAN XL
frames!) to not interfere with other CAN content or the CAN filters
provided by the CAN_RAW sockets and kernel infrastruture.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20240212213550.18516-1-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: uapi: move CAN_RAW_FILTER_MAX definition to raw.h

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 <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20230609121051.9631-1-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: canxl: introduce CAN XL data structure

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 <mailhol.vincent@wanadoo.fr>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20220912170725.120748-5-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: set CANFD_FDF flag in all CAN FD frame structures

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 <mailhol.vincent@wanadoo.fr>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20220912170725.120748-4-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

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

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 <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: uapi: update CAN-FD frame description

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 <kayoub5@live.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

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

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 <lkp@intel.com>
Suggested-by: Rong Chen <rong.a.chen@intel.com>
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 <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: add optional DLC element to Classical CAN frame structure

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 <mailhol.vincent@wanadoo.fr>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/r/20201110101852.1973-2-socketcan@hartkopp.net
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: don't use deprecated license identifiers

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

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: extend sockaddr_can to include j1939 members

This patch prepares struct sockaddr_can for SAE J1939.

Signed-off-by: Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: add socket type for CAN_J1939

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

Signed-off-by: Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: uapi: can.h: Fix can error class mask dir path

The CAN error masks header file is in the
include/uapi directory.

Fix the path in the header to the correct location.

Signed-off-by: Dan Murphy <dmurphy@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

License cleanup: add SPDX license identifier to uapi header files with a license

Many user space API headers have licensing information, which is either
incomplete, badly formatted or just a shorthand for referring to the
license under which the file is supposed to be. This makes it hard for
compliance tools to determine the correct license.

Update these files with an SPDX license identifier. The identifier was
chosen based on the license information in the file.

GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license
identifier with the added 'WITH Linux-syscall-note' exception, which is
the officially assigned exception identifier for the kernel syscall
exception:

NOTE! This copyright does *not* cover user programs that use kernel
services by normal system calls - this is merely considered normal use
of the kernel, and does *not* fall under the heading of "derived work".

This exception makes it possible to include GPL headers into non GPL
code, without confusing license compliance tools.

Headers which have either explicit dual licensing or are just licensed
under a non GPL license are updated with the corresponding SPDX
identifier and the GPLv2 with syscall exception identifier. The format
is:
((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE)

SPDX license identifiers are a legally binding shorthand, which can be
used instead of the full boiler plate text. The update does not remove
existing license information as this has to be done on a case by case
basis and the copyright holders might have to be consulted. This will
happen in a separate step.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne. See the previous patch in this series for the
methodology of how this patch was researched.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

can: raw: raw_setsockopt: limit number of can_filter that can be set

This patch adds a check to limit the number of can_filters that can be
set via setsockopt on CAN_RAW sockets. Otherwise allocations > MAX_ORDER
are not prevented resulting in a warning.

Reference: https://lkml.org/lkml/2016/12/2/230

Reported-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can.h: make padding given by gcc explicit

The current definition of struct can_frame has a 16-byte size, with 8-byte
alignment, but the 3 bytes of padding are not explicit like the similar 2 bytes
of padding of struct canfd_frame. Make it explicit so it is easier to read.

Signed-off-by: Shawn Landden <shawn@churchofgit.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: unify identifiers to ensure unique include processing

Armin pointed me to the fact that the identifier which is used to ensure the
unique include processing in lunux/include/uapi/linux/can.h is CAN_H.
This clashed with his own source as includes from libraries and APIs should
use an underscore '_' at the identifier start.

This patch fixes the protection identifiers in all CAN relavant includes.

Reported-by: Armin Burchardt <armin@uni-bremen.de>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

can: add explicit copyrights to can userspace header

This is in the spirit of commit 2485602f1af2 (can: add explicit
copyrights to can headers). It seems I have missed can.h back then.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

UAPI: (Scripted) Disintegrate include/linux

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Michael Kerrisk <mtk.manpages@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>