1 files changed, 94 insertions, 16 deletions

diff --git a/include/linux/can/skb.h b/include/linux/can/skb.h
index a954def26c0d..1abc25a8d144 100644
--- a/include/linux/can/skb.h
+++ b/include/linux/can/skb.h
@@ -16,6 +16,27 @@
 #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
@@ -29,12 +50,14 @@
  * 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;
-	struct can_frame cf[0];
+	unsigned int frame_len;
+	struct can_frame cf[];
 };
 
 static inline struct can_skb_priv *can_skb_prv(struct sk_buff *skb)
@@ -49,8 +72,12 @@ static inline void can_skb_reserve(struct sk_buff *skb)
 
 static inline void can_skb_set_owner(struct sk_buff *skb, struct sock *sk)
 {
-	if (sk) {
-		sock_hold(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;
 	}
@@ -61,21 +88,72 @@ static inline void can_skb_set_owner(struct sk_buff *skb, struct sock *sk)
  */
 static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb)
 {
-	if (skb_shared(skb)) {
-		struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
-
-		if (likely(nskb)) {
-			can_skb_set_owner(nskb, skb->sk);
-			consume_skb(skb);
-			return nskb;
-		} else {
-			kfree_skb(skb);
-			return NULL;
-		}
+	struct sk_buff *nskb;
+
+	nskb = skb_clone(skb, GFP_ATOMIC);
+	if (unlikely(!nskb)) {
+		kfree_skb(skb);
+		return NULL;
 	}
 
-	/* we can assume to have an unshared skb with proper owner */
-	return skb;
+	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 */