LXR linux/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 * @skbcnt:     atomic counter to have an unique id together with skb pointer
  29 * @cf:         align to the following CAN frame at skb->data
  30 */
  31struct can_skb_priv {
  32        int ifindex;
  33        int skbcnt;
  34        struct can_frame cf[0];
  35};
  36
  37static inline struct can_skb_priv *can_skb_prv(struct sk_buff *skb)
  38{
  39        return (struct can_skb_priv *)(skb->head);
  40}
  41
  42static inline void can_skb_reserve(struct sk_buff *skb)
  43{
  44        skb_reserve(skb, sizeof(struct can_skb_priv));
  45}
  46
  47#endif /* CAN_SKB_H */
  48