1 /* SPDX-License-Identifier: GPL-2.0 */
5 * Definitions for the CAN network socket buffer
7 * Copyright (C) 2012 Oliver Hartkopp <socketcan@hartkopp.net>
14 #include <linux/types.h>
15 #include <linux/skbuff.h>
16 #include <linux/can.h>
20 * The struct can_skb_priv is used to transport additional information along
21 * with the stored struct can(fd)_frame that can not be contained in existing
22 * struct sk_buff elements.
23 * N.B. that this information must not be modified in cloned CAN sk_buffs.
24 * To modify the CAN frame content or the struct can_skb_priv content
25 * skb_copy() needs to be used instead of skb_clone().
29 * struct can_skb_priv - private additional data inside CAN sk_buffs
30 * @ifindex: ifindex of the first interface the CAN frame appeared on
31 * @skbcnt: atomic counter to have an unique id together with skb pointer
32 * @cf: align to the following CAN frame at skb->data
37 struct can_frame cf[0];
40 static inline struct can_skb_priv *can_skb_prv(struct sk_buff *skb)
42 return (struct can_skb_priv *)(skb->head);
45 static inline void can_skb_reserve(struct sk_buff *skb)
47 skb_reserve(skb, sizeof(struct can_skb_priv));
50 static inline void can_skb_set_owner(struct sk_buff *skb, struct sock *sk)
52 /* If the socket has already been closed by user space, the
53 * refcount may already be 0 (and the socket will be freed
54 * after the last TX skb has been freed). So only increase
55 * socket refcount if the refcount is > 0.
57 if (sk && refcount_inc_not_zero(&sk->sk_refcnt)) {
58 skb->destructor = sock_efree;
64 * returns an unshared skb owned by the original sock to be echo'ed back
66 static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb)
70 nskb = skb_clone(skb, GFP_ATOMIC);
71 if (unlikely(!nskb)) {
76 can_skb_set_owner(nskb, skb->sk);
81 #endif /* !_CAN_SKB_H */