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can: raw: fix CAN FD frame transmissions over CAN XL devices

PATCH Superseded Oliver Hartkopp 1 participant 1 message Jan 31, 2023

Subsystems (2)
CAN network drivers CAN network layer

v1 of 4 Superseded Latest is v4 →

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Oliver Hartkopp

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#0 lore raw

PATCH 1/1 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().

Fixes 626332696d75 ("can: raw: add CAN XL support")
Signed-off-by Oliver Hartkopp <[email protected]>
---
 net/can/raw.c | 45 ++++++++++++++++++++++++++++++---------------
 1 file changed, 30 insertions(+), 15 deletions(-)
net/can/raw.c +30 -15
index 81071cdb0301..74fdcec08f48 100644
@@ -130,11 +130,11 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
 	/* check the received tx sock reference */
 	if (!ro->recv_own_msgs && oskb->sk == sk)
 		return;
 
 	/* make sure to not pass oversized frames to the socket */
-	if ((can_is_canfd_skb(oskb) && !ro->fd_frames && !ro->xl_frames) ||
+	if ((can_is_canfd_skb(oskb) && !ro->fd_frames) ||
 	    (can_is_canxl_skb(oskb) && !ro->xl_frames))
 		return;
 
 	/* eliminate multiple filter matches for the same skb */
 	if (this_cpu_ptr(ro->uniq)->skb == oskb &&

@@ -668,19 +668,27 @@ static int raw_setsockopt(struct socket *sock, int level, int optname,
 			return -EINVAL;
 
 		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:
 		if (optlen != sizeof(ro->xl_frames))
 			return -EINVAL;
 
 		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:
 		if (optlen != sizeof(ro->join_filters))
 			return -EINVAL;

@@ -784,10 +792,29 @@ static int raw_getsockopt(struct socket *sock, int level, int optname,
 	if (copy_to_user(optval, val, len))
 		return -EFAULT;
 	return 0;
 }
 
+static bool raw_bad_txframe(struct raw_sock *ro, struct sk_buff *skb, int mtu)
+{
+	/* Classical CAN -> no checks for flags and devive capabilities */
+	if (can_is_can_skb(skb))
+		return false;
+
+	/* CAN FD -> needs to be enabled and a CAN FD or CAN XL device */
+	if (can_is_canfd_skb(skb) && ro->fd_frames &&
+	    (mtu == CANFD_MTU || can_is_canxl_dev_mtu(mtu)))
+		return false;
+
+	/* CAN XL -> needs to be enabled and a CAN XL device */
+	if (can_is_canxl_skb(skb) && ro->xl_frames &&
+	    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;
 	struct raw_sock *ro = raw_sk(sk);
 	struct sockcm_cookie sockc;

@@ -831,24 +858,12 @@ static int raw_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 	err = memcpy_from_msg(skb_put(skb, size), msg, size);
 	if (err < 0)
 		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))
-			goto free_skb;
-	} else {
-		/* Classical CAN */
-		if (!can_is_can_skb(skb))
-			goto free_skb;
-	}
+	if (raw_bad_txframe(ro, skb, dev->mtu))
+		goto free_skb;
 
 	sockcm_init(&sockc, sk);
 	if (msg->msg_controllen) {
 		err = sock_cmsg_send(sk, msg, &sockc);
 		if (unlikely(err))
Signature · 1 line
2.39.0