From 467ef4c7b9d1c22ee64342804bf92549d765df14 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Mon, 12 Sep 2022 19:07:20 +0200 Subject: can: skb: add skb CAN frame data length helpers Add two helpers to retrieve the data length from CAN sk_buffs and prepare the length information to be a uint16 value for the CAN XL support. Acked-by: Vincent Mailhol Signed-off-by: Oliver Hartkopp Link: https://lore.kernel.org/all/20220912170725.120748-3-socketcan@hartkopp.net Signed-off-by: Marc Kleine-Budde --- include/linux/can/skb.h | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/can/skb.h b/include/linux/can/skb.h index 27ebfc28510f..ddffc2fc008c 100644 --- a/include/linux/can/skb.h +++ b/include/linux/can/skb.h @@ -20,7 +20,8 @@ void can_flush_echo_skb(struct net_device *dev); int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev, unsigned int idx, unsigned int frame_len); struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx, - u8 *len_ptr, unsigned int *frame_len_ptr); + unsigned int *len_ptr, + unsigned int *frame_len_ptr); unsigned int __must_check can_get_echo_skb(struct net_device *dev, unsigned int idx, unsigned int *frame_len_ptr); @@ -113,4 +114,25 @@ static inline bool can_is_canfd_skb(const struct sk_buff *skb) return (skb->len == CANFD_MTU && cfd->len <= CANFD_MAX_DLEN); } +/* get length element value from can[fd]_frame structure */ +static inline unsigned int can_skb_get_len_val(struct sk_buff *skb) +{ + const struct canfd_frame *cfd = (struct canfd_frame *)skb->data; + + return cfd->len; +} + +/* get needed data length inside CAN frame for all frame types (RTR aware) */ +static inline unsigned int can_skb_get_data_len(struct sk_buff *skb) +{ + unsigned int len = can_skb_get_len_val(skb); + const struct can_frame *cf = (struct can_frame *)skb->data; + + /* RTR frames have an actual length of zero */ + if (can_is_can_skb(skb) && cf->can_id & CAN_RTR_FLAG) + return 0; + + return len; +} + #endif /* !_CAN_SKB_H */ -- cgit v1.2.3