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80 lines
1.9 KiB
80 lines
1.9 KiB
/* |
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* linux/can/skb.h |
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* |
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* Definitions for the CAN network socket buffer |
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* |
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* Copyright (C) 2012 Oliver Hartkopp <[email protected]> |
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* |
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*/ |
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#ifndef _CAN_SKB_H |
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#define _CAN_SKB_H |
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#include <linux/types.h> |
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#include <linux/skbuff.h> |
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#include <linux/can.h> |
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#include <net/sock.h> |
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/* |
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* The struct can_skb_priv is used to transport additional information along |
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* with the stored struct can(fd)_frame that can not be contained in existing |
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* struct sk_buff elements. |
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* N.B. that this information must not be modified in cloned CAN sk_buffs. |
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* To modify the CAN frame content or the struct can_skb_priv content |
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* skb_copy() needs to be used instead of skb_clone(). |
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*/ |
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/** |
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* struct can_skb_priv - private additional data inside CAN sk_buffs |
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* @ifindex: ifindex of the first interface the CAN frame appeared on |
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* @skbcnt: atomic counter to have an unique id together with skb pointer |
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* @cf: align to the following CAN frame at skb->data |
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*/ |
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struct can_skb_priv { |
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int ifindex; |
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int skbcnt; |
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struct can_frame cf[0]; |
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}; |
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static inline struct can_skb_priv *can_skb_prv(struct sk_buff *skb) |
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{ |
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return (struct can_skb_priv *)(skb->head); |
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} |
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static inline void can_skb_reserve(struct sk_buff *skb) |
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{ |
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skb_reserve(skb, sizeof(struct can_skb_priv)); |
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} |
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static inline void can_skb_set_owner(struct sk_buff *skb, struct sock *sk) |
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{ |
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if (sk) { |
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sock_hold(sk); |
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skb->destructor = sock_efree; |
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skb->sk = sk; |
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} |
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} |
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/* |
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* returns an unshared skb owned by the original sock to be echo'ed back |
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*/ |
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static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb) |
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{ |
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if (skb_shared(skb)) { |
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struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC); |
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if (likely(nskb)) { |
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can_skb_set_owner(nskb, skb->sk); |
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consume_skb(skb); |
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return nskb; |
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} else { |
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kfree_skb(skb); |
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return NULL; |
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} |
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} |
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/* we can assume to have an unshared skb with proper owner */ |
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return skb; |
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} |
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#endif /* !_CAN_SKB_H */
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