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/sock.h> 18 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 u8 *len_ptr, unsigned int *frame_len_ptr); 24 unsigned int __must_check can_get_echo_skb(struct net_device *dev, 25 unsigned int idx, 26 unsigned int *frame_len_ptr); 27 void can_free_echo_skb(struct net_device *dev, unsigned int idx, 28 unsigned int *frame_len_ptr); 29 struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf); 30 struct sk_buff *alloc_canfd_skb(struct net_device *dev, 31 struct canfd_frame **cfd); 32 struct sk_buff *alloc_can_err_skb(struct net_device *dev, 33 struct can_frame **cf); 34 bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb); 35 36 /* 37 * The struct can_skb_priv is used to transport additional information along 38 * with the stored struct can(fd)_frame that can not be contained in existing 39 * struct sk_buff elements. 40 * N.B. that this information must not be modified in cloned CAN sk_buffs. 41 * To modify the CAN frame content or the struct can_skb_priv content 42 * skb_copy() needs to be used instead of skb_clone(). 43 */ 44 45 /** 46 * struct can_skb_priv - private additional data inside CAN sk_buffs 47 * @ifindex: ifindex of the first interface the CAN frame appeared on 48 * @skbcnt: atomic counter to have an unique id together with skb pointer 49 * @frame_len: length of CAN frame in data link layer 50 * @cf: align to the following CAN frame at skb->data 51 */ 52 struct can_skb_priv { 53 int ifindex; 54 int skbcnt; 55 unsigned int frame_len; 56 struct can_frame cf[]; 57 }; 58 59 static inline struct can_skb_priv *can_skb_prv(struct sk_buff *skb) 60 { 61 return (struct can_skb_priv *)(skb->head); 62 } 63 64 static inline void can_skb_reserve(struct sk_buff *skb) 65 { 66 skb_reserve(skb, sizeof(struct can_skb_priv)); 67 } 68 69 static inline void can_skb_set_owner(struct sk_buff *skb, struct sock *sk) 70 { 71 /* If the socket has already been closed by user space, the 72 * refcount may already be 0 (and the socket will be freed 73 * after the last TX skb has been freed). So only increase 74 * socket refcount if the refcount is > 0. 75 */ 76 if (sk && refcount_inc_not_zero(&sk->sk_refcnt)) { 77 skb->destructor = sock_efree; 78 skb->sk = sk; 79 } 80 } 81 82 /* 83 * returns an unshared skb owned by the original sock to be echo'ed back 84 */ 85 static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb) 86 { 87 struct sk_buff *nskb; 88 89 nskb = skb_clone(skb, GFP_ATOMIC); 90 if (unlikely(!nskb)) { 91 kfree_skb(skb); 92 return NULL; 93 } 94 95 can_skb_set_owner(nskb, skb->sk); 96 consume_skb(skb); 97 return nskb; 98 } 99 100 static inline bool can_is_canfd_skb(const struct sk_buff *skb) 101 { 102 /* the CAN specific type of skb is identified by its data length */ 103 return skb->len == CANFD_MTU; 104 } 105 106 #endif /* !_CAN_SKB_H */ 107