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-rw-r--r--Documentation/networking/can.txt6
-rw-r--r--net/can/raw.c26
2 files changed, 5 insertions, 27 deletions
diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt
index f3089d4..0cbe6ec 100644
--- a/Documentation/networking/can.txt
+++ b/Documentation/networking/can.txt
@@ -554,12 +554,6 @@ solution for a couple of reasons:
not specified in the struct can_frame and therefore it is only valid in
CANFD_MTU sized CAN FD frames.
- As long as the payload length is <=8 the received CAN frames from CAN FD
- capable CAN devices can be received and read by legacy sockets too. When
- user-generated CAN FD frames have a payload length <=8 these can be send
- by legacy CAN network interfaces too. Sending CAN FD frames with payload
- length > 8 to a legacy CAN network interface returns an -EMSGSIZE error.
-
Implementation hint for new CAN applications:
To build a CAN FD aware application use struct canfd_frame as basic CAN
diff --git a/net/can/raw.c b/net/can/raw.c
index 8be757c..081e81f 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -121,13 +121,9 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
if (!ro->recv_own_msgs && oskb->sk == sk)
return;
- /* do not pass frames with DLC > 8 to a legacy socket */
- if (!ro->fd_frames) {
- struct canfd_frame *cfd = (struct canfd_frame *)oskb->data;
-
- if (unlikely(cfd->len > CAN_MAX_DLEN))
- return;
- }
+ /* do not pass non-CAN2.0 frames to a legacy socket */
+ if (!ro->fd_frames && oskb->len != CAN_MTU)
+ return;
/* clone the given skb to be able to enqueue it into the rcv queue */
skb = skb_clone(oskb, GFP_ATOMIC);
@@ -738,9 +734,7 @@ static int raw_recvmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *msg, size_t size, int flags)
{
struct sock *sk = sock->sk;
- struct raw_sock *ro = raw_sk(sk);
struct sk_buff *skb;
- int rxmtu;
int err = 0;
int noblock;
@@ -751,20 +745,10 @@ static int raw_recvmsg(struct kiocb *iocb, struct socket *sock,
if (!skb)
return err;
- /*
- * when serving a legacy socket the DLC <= 8 is already checked inside
- * raw_rcv(). Now check if we need to pass a canfd_frame to a legacy
- * socket and cut the possible CANFD_MTU/CAN_MTU length to CAN_MTU
- */
- if (!ro->fd_frames)
- rxmtu = CAN_MTU;
- else
- rxmtu = skb->len;
-
- if (size < rxmtu)
+ if (size < skb->len)
msg->msg_flags |= MSG_TRUNC;
else
- size = rxmtu;
+ size = skb->len;
err = memcpy_toiovec(msg->msg_iov, skb->data, size);
if (err < 0) {
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