[PATCH] can: add a note that RECV_OWN_MSGS frames are subject to filtering

[PATCH] can: add a note that RECV_OWN_MSGS frames are subject to filtering

[Erik Flodin]

Some parts of the documentation may lead the reader to think that the
socket's own frames are always received when CAN_RAW_RECV_OWN_MSGS is
enabled, but all frames are subject to filtering.

As explained by Marc Kleine-Budde:

On TX complete of a CAN frame it's pushed into the RX path of the
networking stack, along with the information of the originating socket.

Then the CAN frame is delivered into AF_CAN, where it is passed on to
all registered receivers depending on filters. One receiver is the
sending socket in CAN_RAW. Then in CAN_RAW the it is checked if the
sending socket has RECV_OWN_MSGS enabled.

Signed-off-by: Erik Flodin <erik@flodin.me>
---
 Documentation/networking/can.rst | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/networking/can.rst b/Documentation/networking/can.rst
index f8dae662e454..f34cb0e4460e 100644
--- a/Documentation/networking/can.rst
+++ b/Documentation/networking/can.rst
@@ -608,6 +608,8 @@ demand:
     setsockopt(s, SOL_CAN_RAW, CAN_RAW_RECV_OWN_MSGS,
                &recv_own_msgs, sizeof(recv_own_msgs));
 
+Note that reception of a socket's own CAN frames are subject to the same
+filtering as other CAN frames (see :ref:`socketcan-rawfilter`).
 
 .. _socketcan-rawfd:
 
-- 
2.31.0

Re: [PATCH] can: add a note that RECV_OWN_MSGS frames are subject to filtering

[Marc Kleine-Budde]

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On 20.04.2021 21:12:00, Erik Flodin wrote:
> Some parts of the documentation may lead the reader to think that the
> socket's own frames are always received when CAN_RAW_RECV_OWN_MSGS is
> enabled, but all frames are subject to filtering.
> 
> As explained by Marc Kleine-Budde:
> 
> On TX complete of a CAN frame it's pushed into the RX path of the
> networking stack, along with the information of the originating socket.
> 
> Then the CAN frame is delivered into AF_CAN, where it is passed on to
> all registered receivers depending on filters. One receiver is the
> sending socket in CAN_RAW. Then in CAN_RAW the it is checked if the
> sending socket has RECV_OWN_MSGS enabled.
> 
> Signed-off-by: Erik Flodin <erik@flodin.me>

Applied to linux-can-next/testing

Thanks,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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