Commit ed3320ce authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
Browse files

can: dev: __can_get_echo_skb(): fix real payload length return value for RTR frames 



The can_get_echo_skb() function returns the number of received bytes to
be used for netdev statistics. In the case of RTR frames we get a valid
(potential non-zero) data length value which has to be passed for further
operations. But on the wire RTR frames have no payload length. Therefore
the value to be used in the statistics has to be zero for RTR frames.

Reported-by: default avatarVincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/r/20201020064443.80164-1-socketcan@hartkopp.net


Fixes: cf5046b3 ("can: dev: let can_get_echo_skb() return dlc of CAN frame")
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 2283f79b

drivers/net/can/dev.c

+6 −2
Original line number Diff line number Diff line
@@ -512,9 +512,13 @@ __can_get_echo_skb(struct net_device *dev, unsigned int idx, u8 *len_ptr) 
		 */

		struct sk_buff *skb = priv->echo_skb[idx];

		struct canfd_frame *cf = (struct canfd_frame *)skb->data;

		u8 len = cf->len;



		*len_ptr = len;

		/* get the real payload length for netdev statistics */

		if (cf->can_id & CAN_RTR_FLAG)

			*len_ptr = 0;

		else

			*len_ptr = cf->len;



		priv->echo_skb[idx] = NULL;



		return skb;