156c2bb9f8
The struct can_skb_priv is used to transport additional information along with the stored struct can(fd)_frame that can not be contained in existing struct sk_buff elements. can_skb_priv is located in the skb headroom, which does not touch the existing CAN sk_buff usage with skb->data and skb->len, so that even out-of-tree CAN drivers can be used without changes. Btw. out-of-tree CAN drivers without can_skb_priv in the sk_buff headroom would not support features based on can_skb_priv. The can_skb_priv->ifindex contains the first interface where the CAN frame appeared on the local host. Unfortunately skb->skb_iif can not be used as this value is overwritten in every netif_receive_skb() call. Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
36 lines
915 B
C
36 lines
915 B
C
/*
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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 <socketcan@hartkopp.net>
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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/can.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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* @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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struct can_frame cf[0];
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};
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#endif /* CAN_SKB_H */
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