kernel-fxtec-pro1x/include/linux/can/dev.h
Oliver Hartkopp c7cd606f60 can: Fix data length code handling in rx path
A valid CAN dataframe can have a data length code (DLC) of 0 .. 8 data bytes.

When reading the CAN controllers register the 4-bit value may contain values
from 0 .. 15 which may exceed the reserved space in the socket buffer!

The ISO 11898-1 Chapter 8.4.2.3 (DLC field) says that register values > 8
should be reduced to 8 without any error reporting or frame drop.

This patch introduces a new helper macro to cast a given 4-bit data length
code (dlc) to __u8 and ensure the DLC value to be max. 8 bytes.

The different handlings in the rx path of the CAN netdevice drivers are fixed.

Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-13 19:47:42 -08:00

84 lines
2.1 KiB
C

/*
* linux/can/dev.h
*
* Definitions for the CAN network device driver interface
*
* Copyright (C) 2006 Andrey Volkov <avolkov@varma-el.com>
* Varma Electronics Oy
*
* Copyright (C) 2008 Wolfgang Grandegger <wg@grandegger.com>
*
* Send feedback to <socketcan-users@lists.berlios.de>
*/
#ifndef CAN_DEV_H
#define CAN_DEV_H
#include <linux/can/netlink.h>
#include <linux/can/error.h>
/*
* CAN mode
*/
enum can_mode {
CAN_MODE_STOP = 0,
CAN_MODE_START,
CAN_MODE_SLEEP
};
/*
* CAN common private data
*/
struct can_priv {
struct can_device_stats can_stats;
struct can_bittiming bittiming;
struct can_bittiming_const *bittiming_const;
struct can_clock clock;
enum can_state state;
u32 ctrlmode;
int restart_ms;
struct timer_list restart_timer;
int (*do_set_bittiming)(struct net_device *dev);
int (*do_set_mode)(struct net_device *dev, enum can_mode mode);
int (*do_get_state)(const struct net_device *dev,
enum can_state *state);
unsigned int echo_skb_max;
struct sk_buff **echo_skb;
};
/*
* get_can_dlc(value) - helper macro to cast a given data length code (dlc)
* to __u8 and ensure the dlc value to be max. 8 bytes.
*
* To be used in the CAN netdriver receive path to ensure conformance with
* ISO 11898-1 Chapter 8.4.2.3 (DLC field)
*/
#define get_can_dlc(i) (min_t(__u8, (i), 8))
struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max);
void free_candev(struct net_device *dev);
int open_candev(struct net_device *dev);
void close_candev(struct net_device *dev);
int register_candev(struct net_device *dev);
void unregister_candev(struct net_device *dev);
int can_restart_now(struct net_device *dev);
void can_bus_off(struct net_device *dev);
void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
unsigned int idx);
void can_get_echo_skb(struct net_device *dev, unsigned int idx);
void can_free_echo_skb(struct net_device *dev, unsigned int idx);
struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf);
struct sk_buff *alloc_can_err_skb(struct net_device *dev,
struct can_frame **cf);
#endif /* CAN_DEV_H */