1 /* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
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>
19 void can_flush_echo_skb(struct net_device *dev);
20 int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
21 unsigned int idx, unsigned int frame_len);
22 struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx,
23 unsigned int *len_ptr,
24 unsigned int *frame_len_ptr);
25 unsigned int __must_check can_get_echo_skb(struct net_device *dev,
27 unsigned int *frame_len_ptr);
28 void can_free_echo_skb(struct net_device *dev, unsigned int idx,
29 unsigned int *frame_len_ptr);
30 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf);
31 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
32 struct canfd_frame **cfd);
33 struct sk_buff *alloc_can_err_skb(struct net_device *dev,
34 struct can_frame **cf);
35 bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb);
38 * The struct can_skb_priv is used to transport additional information along
39 * with the stored struct can(fd)_frame that can not be contained in existing
40 * struct sk_buff elements.
41 * N.B. that this information must not be modified in cloned CAN sk_buffs.
42 * To modify the CAN frame content or the struct can_skb_priv content
43 * skb_copy() needs to be used instead of skb_clone().
47 * struct can_skb_priv - private additional data inside CAN sk_buffs
48 * @ifindex: ifindex of the first interface the CAN frame appeared on
49 * @skbcnt: atomic counter to have an unique id together with skb pointer
50 * @frame_len: length of CAN frame in data link layer
51 * @cf: align to the following CAN frame at skb->data
56 unsigned int frame_len;
57 struct can_frame cf[];
60 static inline struct can_skb_priv *can_skb_prv(struct sk_buff *skb)
62 return (struct can_skb_priv *)(skb->head);
65 static inline void can_skb_reserve(struct sk_buff *skb)
67 skb_reserve(skb, sizeof(struct can_skb_priv));
70 static inline void can_skb_set_owner(struct sk_buff *skb, struct sock *sk)
72 /* If the socket has already been closed by user space, the
73 * refcount may already be 0 (and the socket will be freed
74 * after the last TX skb has been freed). So only increase
75 * socket refcount if the refcount is > 0.
77 if (sk && refcount_inc_not_zero(&sk->sk_refcnt)) {
78 skb->destructor = sock_efree;
84 * returns an unshared skb owned by the original sock to be echo'ed back
86 static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb)
90 nskb = skb_clone(skb, GFP_ATOMIC);
91 if (unlikely(!nskb)) {
96 can_skb_set_owner(nskb, skb->sk);
101 static inline bool can_is_can_skb(const struct sk_buff *skb)
103 struct can_frame *cf = (struct can_frame *)skb->data;
105 /* the CAN specific type of skb is identified by its data length */
106 return (skb->len == CAN_MTU && cf->len <= CAN_MAX_DLEN);
109 static inline bool can_is_canfd_skb(const struct sk_buff *skb)
111 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
113 /* the CAN specific type of skb is identified by its data length */
114 return (skb->len == CANFD_MTU && cfd->len <= CANFD_MAX_DLEN);
117 /* get length element value from can[fd]_frame structure */
118 static inline unsigned int can_skb_get_len_val(struct sk_buff *skb)
120 const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
125 /* get needed data length inside CAN frame for all frame types (RTR aware) */
126 static inline unsigned int can_skb_get_data_len(struct sk_buff *skb)
128 unsigned int len = can_skb_get_len_val(skb);
129 const struct can_frame *cf = (struct can_frame *)skb->data;
131 /* RTR frames have an actual length of zero */
132 if (can_is_can_skb(skb) && cf->can_id & CAN_RTR_FLAG)
138 #endif /* !_CAN_SKB_H */