include/linux/can/skb.h

   1 /*
   2  * linux/can/skb.h
   3  *
   4  * Definitions for the CAN network socket buffer
   5  *
   6  * Copyright (C) 2012 Oliver Hartkopp <socketcan@hartkopp.net>
   7  *
   8  */
   9
  10 #ifndef CAN_SKB_H
  11 #define CAN_SKB_H
  12
  13 #include <linux/types.h>
  14 #include <linux/can.h>
  15
  16 /*
  17  * The struct can_skb_priv is used to transport additional information along
  18  * with the stored struct can(fd)_frame that can not be contained in existing
  19  * struct sk_buff elements.
  20  * N.B. that this information must not be modified in cloned CAN sk_buffs.
  21  * To modify the CAN frame content or the struct can_skb_priv content
  22  * skb_copy() needs to be used instead of skb_clone().
  23  */
  24
  25 /**
  26  * struct can_skb_priv - private additional data inside CAN sk_buffs
  27  * @ifindex:    ifindex of the first interface the CAN frame appeared on
  28  * @cf:         align to the following CAN frame at skb->data
  29  */
  30 struct can_skb_priv {
  31         int ifindex;
  32         struct can_frame cf[0];
  33 };
  34
  35 static inline struct can_skb_priv *can_skb_prv(struct sk_buff *skb)
  36 {
  37         return (struct can_skb_priv *)(skb->head);
  38 }
  39
  40 static inline void can_skb_reserve(struct sk_buff *skb)
  41 {
  42         skb_reserve(skb, sizeof(struct can_skb_priv));
  43 }
  44
  45 #endif /* CAN_SKB_H */