Commit 06183462 authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
Browse files

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: default avatarVincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20220912170725.120748-4-socketcan@hartkopp.net


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 467ef4c7

drivers/net/can/ctucanfd/ctucanfd_base.c

+0 −1
Original line number Diff line number Diff line
@@ -657,7 +657,6 @@ static void ctucan_read_rx_frame(struct ctucan_priv *priv, struct canfd_frame *c 
		cf->can_id = (idw >> 18) & CAN_SFF_MASK;



	/* BRS, ESI, RTR Flags */

	cf->flags = 0;

	if (FIELD_GET(REG_FRAME_FORMAT_W_FDF, ffw)) {

		if (FIELD_GET(REG_FRAME_FORMAT_W_BRS, ffw))

			cf->flags |= CANFD_BRS;

drivers/net/can/dev/skb.c

+11 −0
Original line number Diff line number Diff line
@@ -244,6 +244,9 @@ struct sk_buff *alloc_canfd_skb(struct net_device *dev, 


	*cfd = skb_put_zero(skb, sizeof(struct canfd_frame));



	/* set CAN FD flag by default */

	(*cfd)->flags = CANFD_FDF;



	return skb;

}

EXPORT_SYMBOL_GPL(alloc_canfd_skb);
@@ -287,6 +290,14 @@ static bool can_skb_headroom_valid(struct net_device *dev, struct sk_buff *skb) 
		skb_reset_mac_header(skb);

		skb_reset_network_header(skb);

		skb_reset_transport_header(skb);



		/* set CANFD_FDF flag for CAN FD frames */

		if (can_is_canfd_skb(skb)) {

			struct canfd_frame *cfd;



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

			cfd->flags |= CANFD_FDF;

		}

	}



	return true;

include/uapi/linux/can.h

+2 −2
Original line number Diff line number Diff line
@@ -141,8 +141,8 @@ struct can_frame { 
 * When this is done the former differentiation via CAN_MTU / CANFD_MTU gets

 * 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.

 * Since the introduction of CAN XL the CANFD_FDF flag is set in all CAN FD

 * frame structures provided by the CAN subsystem of the Linux kernel.

 */

#define CANFD_BRS 0x01 /* bit rate switch (second bitrate for payload data) */

#define CANFD_ESI 0x02 /* error state indicator of the transmitting node */

net/can/af_can.c

+5 −0
Original line number Diff line number Diff line
@@ -205,7 +205,12 @@ int can_send(struct sk_buff *skb, int loop) 
	if (can_is_can_skb(skb)) {

		skb->protocol = htons(ETH_P_CAN);

	} else if (can_is_canfd_skb(skb)) {

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



		skb->protocol = htons(ETH_P_CANFD);



		/* set CAN FD flag for CAN FD frames by default */

		cfd->flags |= CANFD_FDF;

	} else {

		goto inval_skb;

	}