Hi,
On Mon, Oct 25, 2021 at 03:30:57PM +0800, Zhang Changzhong wrote:
> On 2021/10/22 18:23, Oleksij Rempel wrote:
> > On Thu, Oct 21, 2021 at 10:04:16PM +0800, Zhang Changzhong wrote:
> >> According to SAE-J1939-82 2015 (A.3.6 Row 2), a receiver should never
> >> send TP.CM_CTS to the global address, so we can add a check in
> >> j1939_can_recv() to drop messages with invalid source address.
> >>
> >> Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
> >> Signed-off-by: Zhang Changzhong <zhangchangzhong@xxxxxxxxxx>
> >
> > NACK. This will break Address Claiming, where first message is SA == 0xff
>
> I know that 0xfe can be used as a source address, but which message has a source
> address of 0xff?
>
> According to SAE-J1939-81 2017 4.2.2.8：
>
> The network address 255, also known as the Global address, is permitted in the
> Destination Address field of the SAE J1939 message identifier but never in the
> Source Address field.
You are right. Thx!
Are you using any testing frameworks?
Can you please take a look here:
https://github.com/linux-can/can-tests/tree/master/j1939
We are using this scripts for regression testing of some know bugs.
>
> >
> >> ---
> >> net/can/j1939/main.c | 4 ++++
> >> 1 file changed, 4 insertions(+)
> >>
> >> diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
> >> index 08c8606..4f1e4bb 100644
> >> --- a/net/can/j1939/main.c
> >> +++ b/net/can/j1939/main.c
> >> @@ -75,6 +75,10 @@ static void j1939_can_recv(struct sk_buff *iskb, void *data)
> >> skcb->addr.pgn = (cf->can_id >> 8) & J1939_PGN_MAX;
> >> /* set default message type */
> >> skcb->addr.type = J1939_TP;
> >> + if (!j1939_address_is_valid(skcb->addr.sa))
> >> + /* ignore messages whose sa is broadcast address */
> >> + goto done;
Please add some warning once message here. We wont to know if something bad
is happening on the bus.
> >> +
> >> if (j1939_pgn_is_pdu1(skcb->addr.pgn)) {
> >> /* Type 1: with destination address */
> >> skcb->addr.da = skcb->addr.pgn;
> >> --
> >> 2.9.5
> >>
> >>
> >>
> >
>
>
Regards,
Oleksij
--
Pengutronix e.K. | |
Steuerwalder Str. 21 | http://www.pengutronix.de/ |
31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
