Commit 3793301c authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
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can: raw: fix CAN FD frame transmissions over CAN XL devices 

A CAN XL device is always capable to process CAN FD frames. The former
check when sending CAN FD frames relied on the existence of a CAN FD
device and did not check for a CAN XL device that would be correct
too.

With this patch the CAN FD feature is enabled automatically when CAN
XL is switched on - and CAN FD cannot be switch off while CAN XL is
enabled.

This precondition also leads to a clean up and reduction of checks in
the hot path in raw_rcv() and raw_sendmsg(). Some conditions are
reordered to handle simple checks first.

changes since v1: https://lore.kernel.org/all/20230131091012.50553-1-socketcan@hartkopp.net
- fixed typo: devive -> device
changes since v2: https://lore.kernel.org/all/20230131091824.51026-1-socketcan@hartkopp.net/


- reorder checks in if statements to handle simple checks first

Fixes: 62633269 ("can: raw: add CAN XL support")
Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20230131105613.55228-1-socketcan@hartkopp.net


Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent d0553680

net/can/raw.c

+31 −16
Original line number Diff line number Diff line
@@ -132,8 +132,8 @@ static void raw_rcv(struct sk_buff *oskb, void *data) 
		return;



	/* make sure to not pass oversized frames to the socket */

	if ((can_is_canfd_skb(oskb) && !ro->fd_frames && !ro->xl_frames) ||

	    (can_is_canxl_skb(oskb) && !ro->xl_frames))

	if ((!ro->fd_frames && can_is_canfd_skb(oskb)) ||

	    (!ro->xl_frames && can_is_canxl_skb(oskb)))

		return;



	/* eliminate multiple filter matches for the same skb */
@@ -670,6 +670,11 @@ static int raw_setsockopt(struct socket *sock, int level, int optname, 
		if (copy_from_sockptr(&ro->fd_frames, optval, optlen))

			return -EFAULT;



		/* Enabling CAN XL includes CAN FD */

		if (ro->xl_frames && !ro->fd_frames) {

			ro->fd_frames = ro->xl_frames;

			return -EINVAL;

		}

		break;



	case CAN_RAW_XL_FRAMES:
@@ -679,6 +684,9 @@ static int raw_setsockopt(struct socket *sock, int level, int optname, 
		if (copy_from_sockptr(&ro->xl_frames, optval, optlen))

			return -EFAULT;



		/* Enabling CAN XL includes CAN FD */

		if (ro->xl_frames)

			ro->fd_frames = ro->xl_frames;

		break;



	case CAN_RAW_JOIN_FILTERS:
@@ -786,6 +794,25 @@ static int raw_getsockopt(struct socket *sock, int level, int optname, 
	return 0;

}



static bool raw_bad_txframe(struct raw_sock *ro, struct sk_buff *skb, int mtu)

{

	/* Classical CAN -> no checks for flags and device capabilities */

	if (can_is_can_skb(skb))

		return false;



	/* CAN FD -> needs to be enabled and a CAN FD or CAN XL device */

	if (ro->fd_frames && can_is_canfd_skb(skb) &&

	    (mtu == CANFD_MTU || can_is_canxl_dev_mtu(mtu)))

		return false;



	/* CAN XL -> needs to be enabled and a CAN XL device */

	if (ro->xl_frames && can_is_canxl_skb(skb) &&

	    can_is_canxl_dev_mtu(mtu))

		return false;



	return true;

}



static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)

{

	struct sock *sk = sock->sk;
@@ -833,20 +860,8 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) 
		goto free_skb;



	err = -EINVAL;

	if (ro->xl_frames && can_is_canxl_dev_mtu(dev->mtu)) {

		/* CAN XL, CAN FD and Classical CAN */

		if (!can_is_canxl_skb(skb) && !can_is_canfd_skb(skb) &&

		    !can_is_can_skb(skb))

			goto free_skb;

	} else if (ro->fd_frames && dev->mtu == CANFD_MTU) {

		/* CAN FD and Classical CAN */

		if (!can_is_canfd_skb(skb) && !can_is_can_skb(skb))

	if (raw_bad_txframe(ro, skb, dev->mtu))

		goto free_skb;

	} else {

		/* Classical CAN */

		if (!can_is_can_skb(skb))

			goto free_skb;

	}



	sockcm_init(&sockc, sk);

	if (msg->msg_controllen) {