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 csx->can_skb_uid = 0;
49 }
50
51 return csx;
52 }
53
can_skb_ext_find(struct sk_buff * skb)54 static inline struct can_skb_ext *can_skb_ext_find(struct sk_buff *skb)
55 {
56 return skb_ext_find(skb, SKB_EXT_CAN);
57 }
58
can_skb_set_owner(struct sk_buff * skb,struct sock * sk)59 static inline void can_skb_set_owner(struct sk_buff *skb, struct sock *sk)
60 {
61 /* If the socket has already been closed by user space, the
62 * refcount may already be 0 (and the socket will be freed
63 * after the last TX skb has been freed). So only increase
64 * socket refcount if the refcount is > 0.
65 */
66 if (sk && refcount_inc_not_zero(&sk->sk_refcnt)) {
67 skb->destructor = sock_efree;
68 skb->sk = sk;
69 }
70 }
71
72 /*
73 * returns an unshared skb owned by the original sock to be echo'ed back
74 */
can_create_echo_skb(struct sk_buff * skb)75 static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb)
76 {
77 struct sk_buff *nskb;
78
79 nskb = skb_clone(skb, GFP_ATOMIC);
80 if (unlikely(!nskb)) {
81 kfree_skb(skb);
82 return NULL;
83 }
84
85 can_skb_set_owner(nskb, skb->sk);
86 consume_skb(skb);
87 return nskb;
88 }
89
can_is_can_skb(const struct sk_buff * skb)90 static inline bool can_is_can_skb(const struct sk_buff *skb)
91 {
92 struct can_frame *cf = (struct can_frame *)skb->data;
93
94 /* the CAN specific type of skb is identified by its data length */
95 return (skb->len == CAN_MTU && cf->len <= CAN_MAX_DLEN);
96 }
97
can_is_canfd_skb(const struct sk_buff * skb)98 static inline bool can_is_canfd_skb(const struct sk_buff *skb)
99 {
100 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
101
102 /* the CAN specific type of skb is identified by its data length */
103 return (skb->len == CANFD_MTU && cfd->len <= CANFD_MAX_DLEN);
104 }
105
can_is_canxl_skb(const struct sk_buff * skb)106 static inline bool can_is_canxl_skb(const struct sk_buff *skb)
107 {
108 const struct canxl_frame *cxl = (struct canxl_frame *)skb->data;
109
110 if (skb->len < CANXL_HDR_SIZE + CANXL_MIN_DLEN || skb->len > CANXL_MTU)
111 return false;
112
113 /* this also checks valid CAN XL data length boundaries */
114 if (skb->len != CANXL_HDR_SIZE + cxl->len)
115 return false;
116
117 return cxl->flags & CANXL_XLF;
118 }
119
120 /* get length element value from can[|fd|xl]_frame structure */
can_skb_get_len_val(struct sk_buff * skb)121 static inline unsigned int can_skb_get_len_val(struct sk_buff *skb)
122 {
123 const struct canxl_frame *cxl = (struct canxl_frame *)skb->data;
124 const struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
125
126 if (can_is_canxl_skb(skb))
127 return cxl->len;
128
129 return cfd->len;
130 }
131
132 /* get needed data length inside CAN frame for all frame types (RTR aware) */
can_skb_get_data_len(struct sk_buff * skb)133 static inline unsigned int can_skb_get_data_len(struct sk_buff *skb)
134 {
135 unsigned int len = can_skb_get_len_val(skb);
136 const struct can_frame *cf = (struct can_frame *)skb->data;
137
138 /* RTR frames have an actual length of zero */
139 if (can_is_can_skb(skb) && cf->can_id & CAN_RTR_FLAG)
140 return 0;
141
142 return len;
143 }
144
145 #endif /* !_CAN_SKB_H */
146