projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 156c2bb9 OH |
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 | ||
| 42193e3e OH |
10 | #ifndef _CAN_SKB_H |
| 11 | #define _CAN_SKB_H | |
| 156c2bb9 OH |
12 | |
| 13 | #include <linux/types.h> | |
| 0ae89beb | 14 | #include <linux/skbuff.h> |
| 156c2bb9 | 15 | #include <linux/can.h> |
| 0ae89beb | 16 | #include <net/sock.h> |
| 156c2bb9 OH |
17 | |
| 18 | /* | |
| 19 | * The struct can_skb_priv is used to transport additional information along | |
| 20 | * with the stored struct can(fd)_frame that can not be contained in existing | |
| 21 | * struct sk_buff elements. | |
| 22 | * N.B. that this information must not be modified in cloned CAN sk_buffs. | |
| 23 | * To modify the CAN frame content or the struct can_skb_priv content | |
| 24 | * skb_copy() needs to be used instead of skb_clone(). | |
| 25 | */ | |
| 26 | ||
| 27 | /** | |
| 28 | * struct can_skb_priv - private additional data inside CAN sk_buffs | |
| 29 | * @ifindex: ifindex of the first interface the CAN frame appeared on | |
| 30 | * @cf: align to the following CAN frame at skb->data | |
| 31 | */ | |
| 32 | struct can_skb_priv { | |
| 33 | int ifindex; | |
| 34 | struct can_frame cf[0]; | |
| 35 | }; | |
| 36 | ||
| 2bf3440d OH |
37 | static inline struct can_skb_priv *can_skb_prv(struct sk_buff *skb) |
| 38 | { | |
| 39 | return (struct can_skb_priv *)(skb->head); | |
| 40 | } | |
| 41 | ||
| 42 | static inline void can_skb_reserve(struct sk_buff *skb) | |
| 43 | { | |
| 44 | skb_reserve(skb, sizeof(struct can_skb_priv)); | |
| 45 | } | |
| 46 | ||
| 0ae89beb OH |
47 | static inline void can_skb_destructor(struct sk_buff *skb) |
| 48 | { | |
| 49 | sock_put(skb->sk); | |
| 50 | } | |
| 51 | ||
| 52 | static inline void can_skb_set_owner(struct sk_buff *skb, struct sock *sk) | |
| 53 | { | |
| 54 | if (sk) { | |
| 55 | sock_hold(sk); | |
| 56 | skb->destructor = can_skb_destructor; | |
| 57 | skb->sk = sk; | |
| 58 | } | |
| 59 | } | |
| 60 | ||
| 61 | /* | |
| 62 | * returns an unshared skb owned by the original sock to be echo'ed back | |
| 63 | */ | |
| 64 | static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb) | |
| 65 | { | |
| 66 | if (skb_shared(skb)) { | |
| 67 | struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC); | |
| 68 | ||
| 69 | if (likely(nskb)) { | |
| 70 | can_skb_set_owner(nskb, skb->sk); | |
| 71 | consume_skb(skb); | |
| 72 | return nskb; | |
| 73 | } else { | |
| 74 | kfree_skb(skb); | |
| 75 | return NULL; | |
| 76 | } | |
| 77 | } | |
| 78 | ||
| 79 | /* we can assume to have an unshared skb with proper owner */ | |
| 80 | return skb; | |
| 81 | } | |
| 82 | ||
| 42193e3e | 83 | #endif /* !_CAN_SKB_H */ |