canfd: add new data structures and constants

- add new struct canfd_frame
- check identical element offsets in struct can_frame and struct canfd_frame
- new ETH_P_CANFD definition to tag CAN FD skbs correctly
- add CAN_MTU and CANFD_MTU definitions for easy frame and mode detection
- add CAN[FD]_MAX_[DLC|DLEN] helper constants to remove hard coded values
- update existing struct can_frame with helper constants and comments

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/if_ether.h b/include/linux/if_ether.h
index 56d907a2c804..167ce5b363d2 100644
--- a/include/linux/if_ether.h
+++ b/include/linux/if_ether.h
@@ -105,7 +105,8 @@
 #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          /* Controller Area Network      */
+#define ETH_P_CAN       0x000C          /* CAN: Controller Area Network */
+#define ETH_P_CANFD     0x000D          /* CANFD: CAN flexible data rate*/
 #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@cafe.net)       */