Re: [RFC PATCH 2/5] can: canxl: introduce ETH_P_CANXL ethernet protocol handling

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 





On 12.07.22 09:17, Marc Kleine-Budde wrote:
On 12.07.2022 09:12:49, Oliver Hartkopp wrote:


On 11.07.22 21:41, Marc Kleine-Budde wrote:
On 11.07.2022 20:34:23, Oliver Hartkopp wrote:
Enable the PF_CAN infrastructure to handle CAN XL frames. A new ethernet
protocol type ETH_P_CANXL is defined to tag skbuffs containing the CAN XL
frame data structure.

As the length information is now a uint16 value for CAN XL a new helper
function can_get_data_len() is introduced to retrieve the data length
from all types of CAN frames.

Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
---
   include/linux/can/skb.h       | 14 ++++++++++
   include/uapi/linux/if_ether.h |  1 +
   net/can/af_can.c              | 49 +++++++++++++++++++++++++++++------
   3 files changed, 56 insertions(+), 8 deletions(-)

diff --git a/include/linux/can/skb.h b/include/linux/can/skb.h
index 182749e858b3..d043bc4afd6d 100644
--- a/include/linux/can/skb.h
+++ b/include/linux/can/skb.h
@@ -101,6 +101,20 @@ static inline bool can_is_canfd_skb(const struct sk_buff *skb)
   {
   	/* the CAN specific type of skb is identified by its data length */
   	return skb->len == CANFD_MTU;
   }
+/* get data length inside of CAN frame for all frame types */
+static inline unsigned int can_get_data_len(struct sk_buff *skb)
+{
+	if(skb->len == CANXL_MTU) {
+		const struct canxl_frame *cfx = (struct canxl_frame *)skb->data;
+
+		return cfx->len;
+	} else {
+		const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
+
+		return cfd->len;
+	}
+}
+
   #endif /* !_CAN_SKB_H */
diff --git a/include/uapi/linux/if_ether.h b/include/uapi/linux/if_ether.h
index d370165bc621..69e0457eb200 100644
--- a/include/uapi/linux/if_ether.h
+++ b/include/uapi/linux/if_ether.h
@@ -136,10 +136,11 @@
   #define ETH_P_WAN_PPP   0x0007          /* Dummy type for WAN PPP frames*/
   #define ETH_P_PPP_MP    0x0008          /* Dummy type for PPP MP frames */
   #define ETH_P_LOCALTALK 0x0009		/* Localtalk pseudo type 	*/
   #define ETH_P_CAN	0x000C		/* CAN: Controller Area Network */
   #define ETH_P_CANFD	0x000D		/* CANFD: CAN flexible data rate*/
+#define ETH_P_CANXL	0x000E		/* CANXL: eXtended frame Length */
   #define ETH_P_PPPTALK	0x0010		/* Dummy type for Atalk over PPP*/
   #define ETH_P_TR_802_2	0x0011		/* 802.2 frames 		*/
   #define ETH_P_MOBITEX	0x0015		/* Mobitex (kaz@xxxxxxxx)	*/
   #define ETH_P_CONTROL	0x0016		/* Card specific control frames */
   #define ETH_P_IRDA	0x0017		/* Linux-IrDA			*/

This file doesn't change that often I suppose. Or does it make sense to
send this change mainline as soon as possible?

AFAIK you only can reserve these values when you have a reference that uses
it. I don't seen any additional pressure here.

There have been added other types that are not used in the kernel (yet).


Ok?!?

I remembered some discussion about PF_FLEXRAY which bounced some years ago.

But I think it should be fine if we get this small patchset discussed and upstreamed to net-next in this round, right?

diff --git a/net/can/af_can.c b/net/can/af_can.c
index 1fb49d51b25d..2c9f48aa5f1f 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -197,31 +197,32 @@ static int can_create(struct net *net, struct socket *sock, int protocol,
    *  -EINVAL when the skb->data does not contain a valid CAN frame
    */
   int can_send(struct sk_buff *skb, int loop)
   {
   	struct sk_buff *newskb = NULL;
-	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
+	unsigned int len = can_get_data_len(skb);
   	struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats;
   	int err = -EINVAL;
   	if (skb->len == CAN_MTU) {
   		skb->protocol = htons(ETH_P_CAN);
-		if (unlikely(cfd->len > CAN_MAX_DLEN))
+		if (unlikely(len > CAN_MAX_DLEN))
   			goto inval_skb;
   	} else if (skb->len == CANFD_MTU) {
   		skb->protocol = htons(ETH_P_CANFD);
-		if (unlikely(cfd->len > CANFD_MAX_DLEN))
+		if (unlikely(len > CANFD_MAX_DLEN))
+			goto inval_skb;
+	} else if (skb->len == CANXL_MTU) {
+		skb->protocol = htons(ETH_P_CANXL);
+		if (unlikely(len > CANXL_MAX_DLEN || len == 0))

Do we need a helper for the > CANXL_MAX_DLEN || == 0 check?

Some can_xl_is_valid_data_size(unsigned int len) ?

In other location you're using "canxl" not "can_xl".

I just thought about can_blablabla() as common namespace for our functions.

But canxl_whatever() is also safe ;-)

What about: canxl_valid_data_size()

Fine for me.

Thanks,
Oliver



[Index of Archives]     [Automotive Discussions]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Security]     [Bugtraq]     [Linux]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]     [CAN Bus]

  Powered by Linux