kernel/linux.git/drivers/net/can/dev/netlink.c, branch v6.1.168

can: netlink: can_changelink(): allow disabling of automatic restart

2025-10-29T13:04:37+00:00

commit 8e93ac51e4c6dc399fad59ec21f55f2cfb46d27c upstream. Since the commit c1f3f9797c1f ("can: netlink: can_changelink(): fix NULL pointer deref of struct can_priv::do_set_mode"), the automatic restart delay can only be set for devices that implement the restart handler struct can_priv::do_set_mode. As it makes no sense to configure a automatic restart for devices that doesn't support it. However, since systemd commit 13ce5d4632e3 ("network/can: properly handle CAN.RestartSec=0") [1], systemd-networkd correctly handles a restart delay of "0" (i.e. the restart is disabled). Which means that a disabled restart is always configured in the kernel. On systems with both changes active this causes that CAN interfaces that don't implement a restart handler cannot be brought up by systemd-networkd. Solve this problem by allowing a delay of "0" to be configured, even if the device does not implement a restart handler. [1] https://github.com/systemd/systemd/commit/13ce5d4632e395521e6205c954493c7fc1c4c6e0 Cc: stable@vger.kernel.org Cc: Andrei Lalaev Reported-by: Marc Kleine-Budde Closes: https://lore.kernel.org/all/20251020-certain-arrogant-vole-of-sunshine-141841-mkl@pengutronix.de Fixes: c1f3f9797c1f ("can: netlink: can_changelink(): fix NULL pointer deref of struct can_priv::do_set_mode") Link: https://patch.msgid.link/20251020-netlink-fix-restart-v1-1-3f53c7f8520b@pengutronix.de Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman

can: netlink: can_changelink(): fix NULL pointer deref of struct can_priv::do_set_mode

2025-08-15T10:04:47+00:00

[ Upstream commit c1f3f9797c1f44a762e6f5f72520b2e520537b52 ] Andrei Lalaev reported a NULL pointer deref when a CAN device is restarted from Bus Off and the driver does not implement the struct can_priv::do_set_mode callback. There are 2 code path that call struct can_priv::do_set_mode: - directly by a manual restart from the user space, via can_changelink() - delayed automatic restart after bus off (deactivated by default) To prevent the NULL pointer deference, refuse a manual restart or configure the automatic restart delay in can_changelink() and report the error via extack to user space. As an additional safety measure let can_restart() return an error if can_priv::do_set_mode is not set instead of dereferencing it unchecked. Reported-by: Andrei Lalaev Closes: https://lore.kernel.org/all/20250714175520.307467-1-andrey.lalaev@gmail.com Fixes: 39549eef3587 ("can: CAN Network device driver and Netlink interface") Link: https://patch.msgid.link/20250718-fix-nullptr-deref-do_set_mode-v1-1-0b520097bb96@pengutronix.de Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin

can: netlink: Fix TDCO calculation using the old data bittiming

2024-02-23T08:12:47+00:00

commit 2aa0a5e65eae27dbd96faca92c84ecbf6f492d42 upstream. The TDCO calculation was done using the currently applied data bittiming, instead of the newly computed data bittiming, which means that the TDCO had an invalid value unless setting the same data bittiming twice. Fixes: d99755f71a80 ("can: netlink: add interface for CAN-FD Transmitter Delay Compensation (TDC)") Signed-off-by: Maxime Jayat Reviewed-by: Vincent Mailhol Link: https://lore.kernel.org/all/40579c18-63c0-43a4-8d4c-f3a6c1c0b417@munic.io Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman

can: netlink: dump bitrate 0 if can_priv::bittiming.bitrate is -1U

2022-07-03T09:34:24+00:00

Upcoming changes on slcan driver will require you to specify a bitrate of value -1 to prevent the open_candev() from failing but at the same time highlighting that it is a fake value. In this case the command `ip --details -s -s link show' would print 4294967295 as the bitrate value. The patch change this value in 0. Link: https://lore.kernel.org/all/20220628163137.413025-5-dario.binacchi@amarulasolutions.com Suggested-by: Marc Kleine-Budde Signed-off-by: Dario Binacchi Tested-by: Jeroen Hofstee Signed-off-by: Marc Kleine-Budde

can: netlink: allow configuring of fixed data bit rates without need for do_set_data_bittiming callback

2022-06-13T16:25:29+00:00

This patch is similar to 7e193a42c37c ("can: netlink: allow configuring of fixed bit rates without need for do_set_bittiming callback") but for data bit rates instead of bit rates. Usually CAN devices support configurable data bit rates. The limits are defined by struct can_priv::data_bittiming_const. Another way is to implement the struct can_priv::do_set_data_bittiming callback. If the bit rate is configured via netlink, the can_changelink() function checks that either can_priv::data_bittiming_const or struct can_priv::do_set_data_bittiming is implemented. In commit 431af779256c ("can: dev: add CAN interface API for fixed bitrates") an API for configuring bit rates on CAN interfaces that only support fixed bit rates was added. The supported bit rates are defined by struct can_priv::bitrate_const. However the above mentioned commit forgot to add the struct can_priv::data_bitrate_const to the check in can_changelink(). In order to avoid to implement a no-op can_priv::do_set_data_bittiming callback on devices with fixed data bit rates, extend the check in can_changelink() accordingly. Link: https://lore.kernel.org/all/20220613143633.4151884-1-mkl@pengutronix.de Fixes: 431af779256c ("can: dev: add CAN interface API for fixed bitrates") Acked-by: Max Staudt Signed-off-by: Marc Kleine-Budde

can: netlink: allow configuring of fixed bit rates without need for do_set_bittiming callback

2022-06-11T15:08:17+00:00

Usually CAN devices support configurable bit rates. The limits are defined by struct can_priv::bittiming_const. Another way is to implement the struct can_priv::do_set_bittiming callback. If the bit rate is configured via netlink, the can_changelink() function checks that either can_priv::bittiming_const or struct can_priv::do_set_bittiming is implemented. In commit 431af779256c ("can: dev: add CAN interface API for fixed bitrates") an API for configuring bit rates on CAN interfaces that only support fixed bit rates was added. The supported bit rates are defined by struct can_priv::bitrate_const. However the above mentioned commit forgot to add the struct can_priv::bitrate_const to the check in can_changelink(). In order to avoid to implement a no-op can_priv::do_set_bittiming callback on devices with fixed bit rates, extend the check in can_changelink() accordingly. Link: https://lore.kernel.org/all/20220611144248.3924903-1-mkl@pengutronix.de Fixes: 431af779256c ("can: dev: add CAN interface API for fixed bitrates") Reported-by: Max Staudt Signed-off-by: Marc Kleine-Budde

can: netlink: report the CAN controller mode supported flags

2022-01-05T11:09:06+00:00

Currently, the CAN netlink interface provides no easy ways to check the capabilities of a given controller. The only method from the command line is to try each CAN_CTRLMODE_* individually to check whether the netlink interface returns an -EOPNOTSUPP error or not (alternatively, one may find it easier to directly check the source code of the driver instead...) This patch introduces a method for the user to check both the supported and the static capabilities. The proposed method introduces a new IFLA nest: IFLA_CAN_CTRLMODE_EXT which extends the current IFLA_CAN_CTRLMODE. This is done to guaranty a full forward and backward compatibility between the kernel and the user land applications. The IFLA_CAN_CTRLMODE_EXT nest contains one single entry: IFLA_CAN_CTRLMODE_SUPPORTED. Because this entry is only used in one direction: kernel to userland, no new struct nla_policy are introduced. Below table explains how IFLA_CAN_CTRLMODE_SUPPORTED (hereafter: "supported") and can_ctrlmode::flags (hereafter: "flags") allow us to identify both the supported and the static capabilities, when masked with any of the CAN_CTRLMODE_* bit flags: supported & flags & Controller capabilities CAN_CTRLMODE_* CAN_CTRLMODE_* ----------------------------------------------------------------------- false false Feature not supported (always disabled) false true Static feature (always enabled) true false Feature supported but disabled true true Feature supported and enabled Link: https://lore.kernel.org/all/20211213160226.56219-5-mailhol.vincent@wanadoo.fr Signed-off-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde

can: dev: replace can_priv::ctrlmode_static by can_get_static_ctrlmode()

2022-01-05T11:09:05+00:00

The statically enabled features of a CAN controller can be retrieved using below formula: | u32 ctrlmode_static = priv->ctrlmode & ~priv->ctrlmode_supported; As such, there is no need to store this information. This patch remove the field ctrlmode_static of struct can_priv and provides, in replacement, the inline function can_get_static_ctrlmode() which returns the same value. Link: https://lore.kernel.org/all/20211213160226.56219-2-mailhol.vincent@wanadoo.fr Signed-off-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde

can: netlink: add can_priv::do_get_auto_tdcv() to retrieve tdcv from device

2021-10-24T14:24:29+00:00

Some CAN device can measure the TDCV (Transmission Delay Compensation Value) automatically for each transmitted CAN frames. A callback function do_get_auto_tdcv() is added to retrieve that value. This function is used only if CAN_CTRLMODE_TDC_AUTO is enabled (if CAN_CTRLMODE_TDC_MANUAL is selected, the TDCV value is provided by the user). If the device does not support reporting of TDCV, do_get_auto_tdcv() should be set to NULL and TDCV will not be reported by the netlink interface. On success, do_get_auto_tdcv() shall return 0. If the value can not be measured by the device, for example because network is down or because no frames were transmitted yet, can_priv::do_get_auto_tdcv() shall return a negative error code (e.g. -EINVAL) to signify that the value is not yet available. In such cases, TDCV is not reported by the netlink interface. Link: https://lore.kernel.org/all/20210918095637.20108-6-mailhol.vincent@wanadoo.fr CC: Stefan Mätje Signed-off-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde

can: netlink: add interface for CAN-FD Transmitter Delay Compensation (TDC)

2021-10-24T14:24:29+00:00

Add the netlink interface for TDC parameters of struct can_tdc_const and can_tdc. Contrary to the can_bittiming(_const) structures for which there is just a single IFLA_CAN(_DATA)_BITTMING(_CONST) entry per structure, here, we create a nested entry IFLA_CAN_TDC. Within this nested entry, additional IFLA_CAN_TDC_TDC* entries are added for each of the TDC parameters of the newly introduced struct can_tdc_const and struct can_tdc. For struct can_tdc_const, these are: IFLA_CAN_TDC_TDCV_MIN IFLA_CAN_TDC_TDCV_MAX IFLA_CAN_TDC_TDCO_MIN IFLA_CAN_TDC_TDCO_MAX IFLA_CAN_TDC_TDCF_MIN IFLA_CAN_TDC_TDCF_MAX For struct can_tdc, these are: IFLA_CAN_TDC_TDCV IFLA_CAN_TDC_TDCO IFLA_CAN_TDC_TDCF This is done so that changes can be applied in the future to the structures without breaking the netlink interface. The TDC netlink logic works as follow: * CAN_CTRLMODE_FD is not provided: - if any TDC parameters are provided: error. - TDC parameters not provided: TDC parameters unchanged. * CAN_CTRLMODE_FD is provided and is false: - TDC is deactivated: both the structure and the CAN_CTRLMODE_TDC_{AUTO,MANUAL} flags are flushed. * CAN_CTRLMODE_FD provided and is true: - CAN_CTRLMODE_TDC_{AUTO,MANUAL} and tdc{v,o,f} not provided: call can_calc_tdco() to automatically decide whether TDC should be activated and, if so, set CAN_CTRLMODE_TDC_AUTO and uses the calculated tdco value. - CAN_CTRLMODE_TDC_AUTO and tdco provided: set CAN_CTRLMODE_TDC_AUTO and use the provided tdco value. Here, tdcv is illegal and tdcf is optional. - CAN_CTRLMODE_TDC_MANUAL and both of tdcv and tdco provided: set CAN_CTRLMODE_TDC_MANUAL and use the provided tdcv and tdco value. Here, tdcf is optional. - CAN_CTRLMODE_TDC_{AUTO,MANUAL} are mutually exclusive. Whenever one flag is turned on, the other will automatically be turned off. Providing both returns an error. - Combination other than the one listed above are illegal and will return an error. N.B. above rules mean that whenever CAN_CTRLMODE_FD is provided, the previous TDC values will be overwritten. The only option to reuse previous TDC value is to not provide CAN_CTRLMODE_FD. All the new parameters are defined as u32. This arbitrary choice is done to mimic the other bittiming values with are also all of type u32. An u16 would have been sufficient to hold the TDC values. This patch completes below series (c.f. [1]): - commit 289ea9e4ae59 ("can: add new CAN FD bittiming parameters: Transmitter Delay Compensation (TDC)") - commit c25cc7993243 ("can: bittiming: add calculation for CAN FD Transmitter Delay Compensation (TDC)") [1] https://lore.kernel.org/linux-can/20210224002008.4158-1-mailhol.vincent@wanadoo.fr/T/#t Link: https://lore.kernel.org/all/20210918095637.20108-5-mailhol.vincent@wanadoo.fr Signed-off-by: Vincent Mailhol Signed-off-by: Marc Kleine-Budde