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Filename : can.h
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/*
 * linux/can.h
 *
 * Definitions for CAN network layer (socket addr / CAN frame / CAN filter)
 *
 * Authors: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
 *          Urs Thuermann   <urs.thuermann@volkswagen.de>
 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
 * All rights reserved.
 *
 */

#ifndef CAN_H
#define CAN_H

#include <linux/types.h>
#include <linux/socket.h>

/* controller area network (CAN) kernel definitions */

/* special address description flags for the CAN_ID */
#define CAN_EFF_FLAG 0x80000000U /* EFF/SFF is set in the MSB */
#define CAN_RTR_FLAG 0x40000000U /* remote transmission request */
#define CAN_ERR_FLAG 0x20000000U /* error message frame */

/* valid bits in CAN ID for frame formats */
#define CAN_SFF_MASK 0x000007FFU /* standard frame format (SFF) */
#define CAN_EFF_MASK 0x1FFFFFFFU /* extended frame format (EFF) */
#define CAN_ERR_MASK 0x1FFFFFFFU /* omit EFF, RTR, ERR flags */

/*
 * Controller Area Network Identifier structure
 *
 * bit 0-28	: CAN identifier (11/29 bit)
 * bit 29	: error message frame flag (0 = data frame, 1 = error message)
 * bit 30	: remote transmission request flag (1 = rtr frame)
 * bit 31	: frame format flag (0 = standard 11 bit, 1 = extended 29 bit)
 */
typedef __u32 canid_t;

#define CAN_SFF_ID_BITS		11
#define CAN_EFF_ID_BITS		29

/*
 * Controller Area Network Error Message Frame Mask structure
 *
 * bit 0-28	: error class mask (see include/linux/can/error.h)
 * bit 29-31	: set to zero
 */
typedef __u32 can_err_mask_t;

/* CAN payload length and DLC definitions according to ISO 11898-1 */
#define CAN_MAX_DLC 8
#define CAN_MAX_DLEN 8

/* CAN FD payload length and DLC definitions according to ISO 11898-7 */
#define CANFD_MAX_DLC 15
#define CANFD_MAX_DLEN 64

/**
 * struct can_frame - basic CAN frame structure
 * @can_id:  CAN ID of the frame and CAN_*_FLAG flags, see canid_t definition
 * @can_dlc: frame payload length in byte (0 .. 8) aka data length code
 *           N.B. the DLC field from ISO 11898-1 Chapter 8.4.2.3 has a 1:1
 *           mapping of the 'data length code' to the real payload length
 * @data:    CAN frame payload (up to 8 byte)
 */
struct can_frame {
	canid_t can_id;  /* 32 bit CAN_ID + EFF/RTR/ERR flags */
	__u8    can_dlc; /* frame payload length in byte (0 .. CAN_MAX_DLEN) */
	__u8    data[CAN_MAX_DLEN] __attribute__((aligned(8)));
};

/*
 * defined bits for canfd_frame.flags
 *
 * The use of struct canfd_frame implies the Extended Data Length (EDL) bit to
 * be set in the CAN frame bitstream on the wire. The EDL bit switch turns
 * the CAN controllers bitstream processor into the CAN FD mode which creates
 * two new options within the CAN FD frame specification:
 *
 * Bit Rate Switch - to indicate a second bitrate is/was used for the payload
 * Error State Indicator - represents the error state of the transmitting node
 *
 * As the CANFD_ESI bit is internally generated by the transmitting CAN
 * controller only the CANFD_BRS bit is relevant for real CAN controllers when
 * building a CAN FD frame for transmission. Setting the CANFD_ESI bit can make
 * sense for virtual CAN interfaces to test applications with echoed frames.
 */
#define CANFD_BRS 0x01 /* bit rate switch (second bitrate for payload data) */
#define CANFD_ESI 0x02 /* error state indicator of the transmitting node */

/**
 * struct canfd_frame - CAN flexible data rate frame structure
 * @can_id: CAN ID of the frame and CAN_*_FLAG flags, see canid_t definition
 * @len:    frame payload length in byte (0 .. CANFD_MAX_DLEN)
 * @flags:  additional flags for CAN FD
 * @__res0: reserved / padding
 * @__res1: reserved / padding
 * @data:   CAN FD frame payload (up to CANFD_MAX_DLEN byte)
 */
struct canfd_frame {
	canid_t can_id;  /* 32 bit CAN_ID + EFF/RTR/ERR flags */
	__u8    len;     /* frame payload length in byte */
	__u8    flags;   /* additional flags for CAN FD */
	__u8    __res0;  /* reserved / padding */
	__u8    __res1;  /* reserved / padding */
	__u8    data[CANFD_MAX_DLEN] __attribute__((aligned(8)));
};

#define CAN_MTU		(sizeof(struct can_frame))
#define CANFD_MTU	(sizeof(struct canfd_frame))

/* particular protocols of the protocol family PF_CAN */
#define CAN_RAW		1 /* RAW sockets */
#define CAN_BCM		2 /* Broadcast Manager */
#define CAN_TP16	3 /* VAG Transport Protocol v1.6 */
#define CAN_TP20	4 /* VAG Transport Protocol v2.0 */
#define CAN_MCNET	5 /* Bosch MCNet */
#define CAN_ISOTP	6 /* ISO 15765-2 Transport Protocol */
#define CAN_NPROTO	7

#define SOL_CAN_BASE 100

/**
 * struct sockaddr_can - the sockaddr structure for CAN sockets
 * @can_family:  address family number AF_CAN.
 * @can_ifindex: CAN network interface index.
 * @can_addr:    protocol specific address information
 */
struct sockaddr_can {
	__kernel_sa_family_t can_family;
	int         can_ifindex;
	union {
		/* transport protocol class address information (e.g. ISOTP) */
		struct { canid_t rx_id, tx_id; } tp;

		/* reserved for future CAN protocols address information */
	} can_addr;
};

/**
 * struct can_filter - CAN ID based filter in can_register().
 * @can_id:   relevant bits of CAN ID which are not masked out.
 * @can_mask: CAN mask (see description)
 *
 * Description:
 * A filter matches, when
 *
 *          <received_can_id> & mask == can_id & mask
 *
 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
 * filter for error message frames (CAN_ERR_FLAG bit set in mask).
 */
struct can_filter {
	canid_t can_id;
	canid_t can_mask;
};

#define CAN_INV_FILTER 0x20000000U /* to be set in can_filter.can_id */

#endif /* CAN_H */