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/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
/*
* linux/can/skb.h
*
* Definitions for the CAN network socket buffer
*
* Copyright (C) 2012 Oliver Hartkopp <socketcan@hartkopp.net>
*
*/
#ifndef _CAN_SKB_H
#define _CAN_SKB_H
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/can.h>
#include <net/sock.h>
void can_flush_echo_skb(struct net_device *dev);
int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
unsigned int idx, unsigned int frame_len);
struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx,
unsigned int *len_ptr,
unsigned int *frame_len_ptr);
unsigned int __must_check can_get_echo_skb(struct net_device *dev,
unsigned int idx,
unsigned int *frame_len_ptr);
void can_free_echo_skb(struct net_device *dev, unsigned int idx,
unsigned int *frame_len_ptr);
struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf);
struct sk_buff *alloc_canfd_skb(struct net_device *dev,
struct canfd_frame **cfd);
struct sk_buff *alloc_canxl_skb(struct net_device *dev,
struct canxl_frame **cxl,
unsigned int data_len);
struct sk_buff *alloc_can_err_skb(struct net_device *dev,
struct can_frame **cf);
bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb);
/*
* 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.
* N.B. that this information must not be modified in cloned CAN sk_buffs.
* To modify the CAN frame content or the struct can_skb_priv content
* skb_copy() needs to be used instead of skb_clone().
*/
/**
* struct can_skb_priv - private additional data inside CAN sk_buffs
* @ifindex: ifindex of the first interface the CAN frame appeared on
* @skbcnt: atomic counter to have an unique id together with skb pointer
* @frame_len: length of CAN frame in data link layer
* @cf: align to the following CAN frame at skb->data
*/
struct can_skb_priv {
int ifindex;
int skbcnt;
unsigned int frame_len;
struct can_frame cf[];
};
static inline struct can_skb_priv *can_skb_prv(struct sk_buff *skb)
{
return (struct can_skb_priv *)(skb->head);
}
static inline void can_skb_reserve(struct sk_buff *skb)
{
skb_reserve(skb, sizeof(struct can_skb_priv));
}
static inline void can_skb_set_owner(struct sk_buff *skb, struct sock *sk)
{
/* If the socket has already been closed by user space, the
* refcount may already be 0 (and the socket will be freed
* after the last TX skb has been freed). So only increase
* socket refcount if the refcount is > 0.
*/
if (sk && refcount_inc_not_zero(&sk->sk_refcnt)) {
skb->destructor = sock_efree;
skb->sk = sk;
}
}
/*
* returns an unshared skb owned by the original sock to be echo'ed back
*/
static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb)
{
struct sk_buff *nskb;
nskb = skb_clone(skb, GFP_ATOMIC);
if (unlikely(!nskb)) {
kfree_skb(skb);
return NULL;
}
can_skb_set_owner(nskb, skb->sk);
consume_skb(skb);
return nskb;
}
static inline bool can_is_can_skb(const struct sk_buff *skb)
{
struct can_frame *cf = (struct can_frame *)skb->data;
/* the CAN specific type of skb is identified by its data length */
return (skb->len == CAN_MTU && cf->len <= CAN_MAX_DLEN);
}
static inline bool can_is_canfd_skb(const struct sk_buff *skb)
{
struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
/* the CAN specific type of skb is identified by its data length */
return (skb->len == CANFD_MTU && cfd->len <= CANFD_MAX_DLEN);
}
static inline bool can_is_canxl_skb(const struct sk_buff *skb)
{
const struct canxl_frame *cxl = (struct canxl_frame *)skb->data;
if (skb->len < CANXL_HDR_SIZE + CANXL_MIN_DLEN || skb->len > CANXL_MTU)
return false;
/* this also checks valid CAN XL data length boundaries */
if (skb->len != CANXL_HDR_SIZE + cxl->len)
return false;
return cxl->flags & CANXL_XLF;
}
/* get length element value from can[|fd|xl]_frame structure */
static inline unsigned int can_skb_get_len_val(struct sk_buff *skb)
{
const struct canxl_frame *cxl = (struct canxl_frame *)skb->data;
const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
if (can_is_canxl_skb(skb))
return cxl->len;
return cfd->len;
}
/* get needed data length inside CAN frame for all frame types (RTR aware) */
static inline unsigned int can_skb_get_data_len(struct sk_buff *skb)
{
unsigned int len = can_skb_get_len_val(skb);
const struct can_frame *cf = (struct can_frame *)skb->data;
/* RTR frames have an actual length of zero */
if (can_is_can_skb(skb) && cf->can_id & CAN_RTR_FLAG)
return 0;
return len;
}
#endif /* !_CAN_SKB_H */