can-gw: add netlink based CAN routing

header-y += raw.h

header-y += bcm.h

header-y += gw.h

header-y += error.h

header-y += netlink.h

/*

 * 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.

 *

 * Send feedback to <socketcan-users@lists.berlios.de>

 *

 */

#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_MAX

};

#define CGW_MAX (__CGW_MAX - 1)

#define CGW_FLAGS_CAN_ECHO 0x01

#define CGW_FLAGS_CAN_SRC_TSTAMP 0x02

#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

#define CGW_MOD_DATA	0x04

#define CGW_FRAME_MODS 3 /* ID DLC DATA */

#define MAX_MODFUNCTIONS (CGW_MOD_FUNCS * CGW_FRAME_MODS)

struct cgw_frame_mod {

	struct can_frame cf;

	__u8 modtype;

} __attribute__((packed));

#define CGW_MODATTR_LEN sizeof(struct cgw_frame_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_XXX (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_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

	  CAN messages are used on the bus (e.g. in automotive environments).

	  To use the Broadcast Manager, use AF_CAN with protocol CAN_BCM.

config CAN_GW

	tristate "CAN Gateway/Router (with netlink configuration)"

	depends on CAN

	default N

	---help---

	  The CAN Gateway/Router is used to route (and modify) CAN frames.

	  It is based on the PF_CAN core infrastructure for msg filtering and

	  msg sending and can optionally modify routed CAN frames on the fly.

	  CAN frames can be routed between CAN network interfaces (one hop).

	  They can be modified with AND/OR/XOR/SET operations as configured

	  by the netlink configuration interface known e.g. from iptables.

source "drivers/net/can/Kconfig"

obj-$(CONFIG_CAN_BCM)	+= can-bcm.o

can-bcm-y		:= bcm.o

obj-$(CONFIG_CAN_GW)	+= can-gw.o

can-gw-y		:= gw.o