1 /* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
2 /*
3 * linux/can/skb.h
4 *
5 * Definitions for the CAN network socket buffer
6 *
7 * Copyright (C) 2012 Oliver Hartkopp <socketcan@hartkopp.net>
8 *
9 */
10
11 #ifndef _CAN_SKB_H
12 #define _CAN_SKB_H
13
14 #include <linux/types.h>
15 #include <linux/skbuff.h>
16 #include <linux/can.h>
17 #include <net/can.h>
18 #include <net/sock.h>
19
20 void can_flush_echo_skb(struct net_device *dev);
21 int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
22 unsigned int idx, unsigned int frame_len);
23 struct sk_buff *__can_get_echo_skb(struct net_device *dev, unsigned int idx,
24 unsigned int *len_ptr,
25 unsigned int *frame_len_ptr);
26 unsigned int __must_check can_get_echo_skb(struct net_device *dev,
27 unsigned int idx,
28 unsigned int *frame_len_ptr);
29 void can_free_echo_skb(struct net_device *dev, unsigned int idx,
30 unsigned int *frame_len_ptr);
31 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf);
32 struct sk_buff *alloc_canfd_skb(struct net_device *dev,
33 struct canfd_frame **cfd);
34 struct sk_buff *alloc_canxl_skb(struct net_device *dev,
35 struct canxl_frame **cxl,
36 unsigned int data_len);
37 struct sk_buff *alloc_can_err_skb(struct net_device *dev,
38 struct can_frame **cf);
39 bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb);
40
can_skb_ext_add(struct sk_buff * skb)41 static inline struct can_skb_ext *can_skb_ext_add(struct sk_buff *skb)
42 {
43 struct can_skb_ext *csx = skb_ext_add(skb, SKB_EXT_CAN);
44
45 /* skb_ext_add() returns uninitialized space */
46 if (csx)
47 csx->can_gw_hops = 0;
48
49 return csx;
50 }
51
can_skb_ext_find(struct sk_buff * skb)52 static inline struct can_skb_ext *can_skb_ext_find(struct sk_buff *skb)
53 {
54 return skb_ext_find(skb, SKB_EXT_CAN);
55 }
56
can_skb_set_owner(struct sk_buff * skb,struct sock * sk)57 static inline void can_skb_set_owner(struct sk_buff *skb, struct sock *sk)
58 {
59 /* If the socket has already been closed by user space, the
60 * refcount may already be 0 (and the socket will be freed
61 * after the last TX skb has been freed). So only increase
62 * socket refcount if the refcount is > 0.
63 */
64 if (sk && refcount_inc_not_zero(&sk->sk_refcnt)) {
65 skb->destructor = sock_efree;
66 skb->sk = sk;
67 }
68 }
69
70 /*
71 * returns an unshared skb owned by the original sock to be echo'ed back
72 */
can_create_echo_skb(struct sk_buff * skb)73 static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb)
74 {
75 struct sk_buff *nskb;
76
77 nskb = skb_clone(skb, GFP_ATOMIC);
78 if (unlikely(!nskb)) {
79 kfree_skb(skb);
80 return NULL;
81 }
82
83 can_skb_set_owner(nskb, skb->sk);
84 consume_skb(skb);
85 return nskb;
86 }
87
can_is_can_skb(const struct sk_buff * skb)88 static inline bool can_is_can_skb(const struct sk_buff *skb)
89 {
90 struct can_frame *cf = (struct can_frame *)skb->data;
91
92 /* the CAN specific type of skb is identified by its data length */
93 return (skb->len == CAN_MTU && cf->len <= CAN_MAX_DLEN);
94 }
95
can_is_canfd_skb(const struct sk_buff * skb)96 static inline bool can_is_canfd_skb(const struct sk_buff *skb)
97 {
98 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
99
100 /* the CAN specific type of skb is identified by its data length */
101 return (skb->len == CANFD_MTU && cfd->len <= CANFD_MAX_DLEN);
102 }
103
can_is_canxl_skb(const struct sk_buff * skb)104 static inline bool can_is_canxl_skb(const struct sk_buff *skb)
105 {
106 const struct canxl_frame *cxl = (struct canxl_frame *)skb->data;
107
108 if (skb->len < CANXL_HDR_SIZE + CANXL_MIN_DLEN || skb->len > CANXL_MTU)
109 return false;
110
111 /* this also checks valid CAN XL data length boundaries */
112 if (skb->len != CANXL_HDR_SIZE + cxl->len)
113 return false;
114
115 return cxl->flags & CANXL_XLF;
116 }
117
118 /* get length element value from can[|fd|xl]_frame structure */
can_skb_get_len_val(struct sk_buff * skb)119 static inline unsigned int can_skb_get_len_val(struct sk_buff *skb)
120 {
121 const struct canxl_frame *cxl = (struct canxl_frame *)skb->data;
122 const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
123
124 if (can_is_canxl_skb(skb))
125 return cxl->len;
126
127 return cfd->len;
128 }
129
130 /* get needed data length inside CAN frame for all frame types (RTR aware) */
can_skb_get_data_len(struct sk_buff * skb)131 static inline unsigned int can_skb_get_data_len(struct sk_buff *skb)
132 {
133 unsigned int len = can_skb_get_len_val(skb);
134 const struct can_frame *cf = (struct can_frame *)skb->data;
135
136 /* RTR frames have an actual length of zero */
137 if (can_is_can_skb(skb) && cf->can_id & CAN_RTR_FLAG)
138 return 0;
139
140 return len;
141 }
142
143 #endif /* !_CAN_SKB_H */
144