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/usr/include/linux/can

Name	Size	Mode	Actions
bcm.h	4116	0644	edit dl rm
error.h	6654	0644	edit dl rm
gw.h	8026	0644	edit dl rm
isotp.h	7427	0644	edit dl rm
j1939.h	2403	0644	edit dl rm
netlink.h	4225	0644	edit dl rm
raw.h	2895	0644	edit dl rm
vxcan.h	232	0644	edit dl rm

Edit: /usr/include/linux/can/gw.h (8026B)

/* SPDX-License-Identifier: ((GPL-2.0-only WITH Linux-syscall-note) OR BSD-3-Clause) */
/*
 * linux/can/gw.h
 *
 * Definitions for CAN frame Gateway/Router/Bridge
 *
 * Author: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
 * Copyright (c) 2011 Volkswagen Group Electronic Research
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of Volkswagen nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * Alternatively, provided that this notice is retained in full, this
 * software may be distributed under the terms of the GNU General
 * Public License ("GPL") version 2, in which case the provisions of the
 * GPL apply INSTEAD OF those given above.
 *
 * The provided data structures and external interfaces from this code
 * are not restricted to be used by modules with a GPL compatible license.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 */

#ifndef _CAN_GW_H
#define _CAN_GW_H

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

struct rtcanmsg {
	__u8  can_family;
	__u8  gwtype;
	__u16 flags;
};

/* CAN gateway types */
enum {
	CGW_TYPE_UNSPEC,
	CGW_TYPE_CAN_CAN,	/* CAN->CAN routing */
	__CGW_TYPE_MAX
};

#define CGW_TYPE_MAX (__CGW_TYPE_MAX - 1)

/* CAN rtnetlink attribute definitions */
enum {
	CGW_UNSPEC,
	CGW_MOD_AND,	/* CAN frame modification binary AND */
	CGW_MOD_OR,	/* CAN frame modification binary OR */
	CGW_MOD_XOR,	/* CAN frame modification binary XOR */
	CGW_MOD_SET,	/* CAN frame modification set alternate values */
	CGW_CS_XOR,	/* set data[] XOR checksum into data[index] */
	CGW_CS_CRC8,	/* set data[] CRC8 checksum into data[index] */
	CGW_HANDLED,	/* number of handled CAN frames */
	CGW_DROPPED,	/* number of dropped CAN frames */
	CGW_SRC_IF,	/* ifindex of source network interface */
	CGW_DST_IF,	/* ifindex of destination network interface */
	CGW_FILTER,	/* specify struct can_filter on source CAN device */
	CGW_DELETED,	/* number of deleted CAN frames (see max_hops param) */
	CGW_LIM_HOPS,	/* limit the number of hops of this specific rule */
	CGW_MOD_UID,	/* user defined identifier for modification updates */
	CGW_FDMOD_AND,	/* CAN FD frame modification binary AND */
	CGW_FDMOD_OR,	/* CAN FD frame modification binary OR */
	CGW_FDMOD_XOR,	/* CAN FD frame modification binary XOR */
	CGW_FDMOD_SET,	/* CAN FD frame modification set alternate values */
	__CGW_MAX
};

#define CGW_MAX (__CGW_MAX - 1)

#define CGW_FLAGS_CAN_ECHO 0x01
#define CGW_FLAGS_CAN_SRC_TSTAMP 0x02
#define CGW_FLAGS_CAN_IIF_TX_OK 0x04
#define CGW_FLAGS_CAN_FD 0x08

#define CGW_MOD_FUNCS 4 /* AND OR XOR SET */

/* CAN frame elements that are affected by curr. 3 CAN frame modifications */
#define CGW_MOD_ID	0x01
#define CGW_MOD_DLC	0x02		/* Classical CAN data length code */
#define CGW_MOD_LEN	CGW_MOD_DLC	/* CAN FD (plain) data length */
#define CGW_MOD_DATA	0x04
#define CGW_MOD_FLAGS	0x08		/* CAN FD flags */

#define CGW_FRAME_MODS 4 /* ID DLC/LEN DATA FLAGS */

#define MAX_MODFUNCTIONS (CGW_MOD_FUNCS * CGW_FRAME_MODS)

struct cgw_frame_mod {
	struct can_frame cf;
	__u8 modtype;
} __attribute__((packed));

struct cgw_fdframe_mod {
	struct canfd_frame cf;
	__u8 modtype;
} __attribute__((packed));

#define CGW_MODATTR_LEN sizeof(struct cgw_frame_mod)
#define CGW_FDMODATTR_LEN sizeof(struct cgw_fdframe_mod)

struct cgw_csum_xor {
	__s8 from_idx;
	__s8 to_idx;
	__s8 result_idx;
	__u8 init_xor_val;
} __attribute__((packed));

struct cgw_csum_crc8 {
	__s8 from_idx;
	__s8 to_idx;
	__s8 result_idx;
	__u8 init_crc_val;
	__u8 final_xor_val;
	__u8 crctab[256];
	__u8 profile;
	__u8 profile_data[20];
} __attribute__((packed));

/* length of checksum operation parameters. idx = index in CAN frame data[] */
#define CGW_CS_XOR_LEN  sizeof(struct cgw_csum_xor)
#define CGW_CS_CRC8_LEN  sizeof(struct cgw_csum_crc8)

/* CRC8 profiles (compute CRC for additional data elements - see below) */
enum {
	CGW_CRC8PRF_UNSPEC,
	CGW_CRC8PRF_1U8,	/* compute one additional u8 value */
	CGW_CRC8PRF_16U8,	/* u8 value table indexed by data[1] & 0xF */
	CGW_CRC8PRF_SFFID_XOR,	/* (can_id & 0xFF) ^ (can_id >> 8 & 0xFF) */
	__CGW_CRC8PRF_MAX
};

#define CGW_CRC8PRF_MAX (__CGW_CRC8PRF_MAX - 1)

/*
 * CAN rtnetlink attribute contents in detail
 *
 * CGW_XXX_IF (length 4 bytes):
 * Sets an interface index for source/destination network interfaces.
 * For the CAN->CAN gwtype the indices of _two_ CAN interfaces are mandatory.
 *
 * CGW_FILTER (length 8 bytes):
 * Sets a CAN receive filter for the gateway job specified by the
 * struct can_filter described in include/linux/can.h
 *
 * CGW_MOD_(AND|OR|XOR|SET) (length 17 bytes):
 * Specifies a modification that's done to a received CAN frame before it is
 * send out to the destination interface.
 *
 * <struct can_frame> data used as operator
 * <u8> affected CAN frame elements
 *
 * CGW_LIM_HOPS (length 1 byte):
 * Limit the number of hops of this specific rule. Usually the received CAN
 * frame can be processed as much as 'max_hops' times (which is given at module
 * load time of the can-gw module). This value is used to reduce the number of
 * possible hops for this gateway rule to a value smaller then max_hops.
 *
 * CGW_MOD_UID (length 4 bytes):
 * Optional non-zero user defined routing job identifier to alter existing
 * modification settings at runtime.
 *
 * CGW_CS_XOR (length 4 bytes):
 * Set a simple XOR checksum starting with an initial value into
 * data[result-idx] using data[start-idx] .. data[end-idx]
 *
 * The XOR checksum is calculated like this:
 *
 * xor = init_xor_val
 *
 * for (i = from_idx .. to_idx)
 *      xor ^= can_frame.data[i]
 *
 * can_frame.data[ result_idx ] = xor
 *
 * CGW_CS_CRC8 (length 282 bytes):
 * Set a CRC8 value into data[result-idx] using a given 256 byte CRC8 table,
 * a given initial value and a defined input data[start-idx] .. data[end-idx].
 * Finally the result value is XOR'ed with the final_xor_val.
 *
 * The CRC8 checksum is calculated like this:
 *
 * crc = init_crc_val
 *
 * for (i = from_idx .. to_idx)
 *      crc = crctab[ crc ^ can_frame.data[i] ]
 *
 * can_frame.data[ result_idx ] = crc ^ final_xor_val
 *
 * The calculated CRC may contain additional source data elements that can be
 * defined in the handling of 'checksum profiles' e.g. shown in AUTOSAR specs
 * like http://www.autosar.org/download/R4.0/AUTOSAR_SWS_E2ELibrary.pdf
 * E.g. the profile_data[] may contain additional u8 values (called DATA_IDs)
 * that are used depending on counter values inside the CAN frame data[].
 * So far only three profiles have been implemented for illustration.
 *
 * Remark: In general the attribute data is a linear buffer.
 *         Beware of sending unpacked or aligned structs!
 */

#endif /* !_UAPI_CAN_GW_H */

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