include/uapi/linux/can/gw.h

   1 /* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
   2 /*
   3  * linux/can/gw.h
   4  *
   5  * Definitions for CAN frame Gateway/Router/Bridge
   6  *
   7  * Author: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
   8  * Copyright (c) 2011 Volkswagen Group Electronic Research
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. Neither the name of Volkswagen nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * Alternatively, provided that this notice is retained in full, this
  24  * software may be distributed under the terms of the GNU General
  25  * Public License ("GPL") version 2, in which case the provisions of the
  26  * GPL apply INSTEAD OF those given above.
  27  *
  28  * The provided data structures and external interfaces from this code
  29  * are not restricted to be used by modules with a GPL compatible license.
  30  *
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  36  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  37  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  38  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  39  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  40  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  41  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
  42  * DAMAGE.
  43  */
  44
  45 #ifndef _UAPI_CAN_GW_H
  46 #define _UAPI_CAN_GW_H
  47
  48 #include <linux/types.h>
  49 #include <linux/can.h>
  50
  51 struct rtcanmsg {
  52         __u8  can_family;
  53         __u8  gwtype;
  54         __u16 flags;
  55 };
  56
  57 /* CAN gateway types */
  58 enum {
  59         CGW_TYPE_UNSPEC,
  60         CGW_TYPE_CAN_CAN,       /* CAN->CAN routing */
  61         __CGW_TYPE_MAX
  62 };
  63
  64 #define CGW_TYPE_MAX (__CGW_TYPE_MAX - 1)
  65
  66 /* CAN rtnetlink attribute definitions */
  67 enum {
  68         CGW_UNSPEC,
  69         CGW_MOD_AND,    /* CAN frame modification binary AND */
  70         CGW_MOD_OR,     /* CAN frame modification binary OR */
  71         CGW_MOD_XOR,    /* CAN frame modification binary XOR */
  72         CGW_MOD_SET,    /* CAN frame modification set alternate values */
  73         CGW_CS_XOR,     /* set data[] XOR checksum into data[index] */
  74         CGW_CS_CRC8,    /* set data[] CRC8 checksum into data[index] */
  75         CGW_HANDLED,    /* number of handled CAN frames */
  76         CGW_DROPPED,    /* number of dropped CAN frames */
  77         CGW_SRC_IF,     /* ifindex of source network interface */
  78         CGW_DST_IF,     /* ifindex of destination network interface */
  79         CGW_FILTER,     /* specify struct can_filter on source CAN device */
  80         CGW_DELETED,    /* number of deleted CAN frames (see max_hops param) */
  81         CGW_LIM_HOPS,   /* limit the number of hops of this specific rule */
  82         CGW_MOD_UID,    /* user defined identifier for modification updates */
  83         __CGW_MAX
  84 };
  85
  86 #define CGW_MAX (__CGW_MAX - 1)
  87
  88 #define CGW_FLAGS_CAN_ECHO 0x01
  89 #define CGW_FLAGS_CAN_SRC_TSTAMP 0x02
  90 #define CGW_FLAGS_CAN_IIF_TX_OK 0x04
  91
  92 #define CGW_MOD_FUNCS 4 /* AND OR XOR SET */
  93
  94 /* CAN frame elements that are affected by curr. 3 CAN frame modifications */
  95 #define CGW_MOD_ID      0x01
  96 #define CGW_MOD_DLC     0x02
  97 #define CGW_MOD_DATA    0x04
  98
  99 #define CGW_FRAME_MODS 3 /* ID DLC DATA */
 100
 101 #define MAX_MODFUNCTIONS (CGW_MOD_FUNCS * CGW_FRAME_MODS)
 102
 103 struct cgw_frame_mod {
 104         struct can_frame cf;
 105         __u8 modtype;
 106 } __attribute__((packed));
 107
 108 #define CGW_MODATTR_LEN sizeof(struct cgw_frame_mod)
 109
 110 struct cgw_csum_xor {
 111         __s8 from_idx;
 112         __s8 to_idx;
 113         __s8 result_idx;
 114         __u8 init_xor_val;
 115 } __attribute__((packed));
 116
 117 struct cgw_csum_crc8 {
 118         __s8 from_idx;
 119         __s8 to_idx;
 120         __s8 result_idx;
 121         __u8 init_crc_val;
 122         __u8 final_xor_val;
 123         __u8 crctab[256];
 124         __u8 profile;
 125         __u8 profile_data[20];
 126 } __attribute__((packed));
 127
 128 /* length of checksum operation parameters. idx = index in CAN frame data[] */
 129 #define CGW_CS_XOR_LEN  sizeof(struct cgw_csum_xor)
 130 #define CGW_CS_CRC8_LEN  sizeof(struct cgw_csum_crc8)
 131
 132 /* CRC8 profiles (compute CRC for additional data elements - see below) */
 133 enum {
 134         CGW_CRC8PRF_UNSPEC,
 135         CGW_CRC8PRF_1U8,        /* compute one additional u8 value */
 136         CGW_CRC8PRF_16U8,       /* u8 value table indexed by data[1] & 0xF */
 137         CGW_CRC8PRF_SFFID_XOR,  /* (can_id & 0xFF) ^ (can_id >> 8 & 0xFF) */
 138         __CGW_CRC8PRF_MAX
 139 };
 140
 141 #define CGW_CRC8PRF_MAX (__CGW_CRC8PRF_MAX - 1)
 142
 143 /*
 144  * CAN rtnetlink attribute contents in detail
 145  *
 146  * CGW_XXX_IF (length 4 bytes):
 147  * Sets an interface index for source/destination network interfaces.
 148  * For the CAN->CAN gwtype the indices of _two_ CAN interfaces are mandatory.
 149  *
 150  * CGW_FILTER (length 8 bytes):
 151  * Sets a CAN receive filter for the gateway job specified by the
 152  * struct can_filter described in include/linux/can.h
 153  *
 154  * CGW_MOD_(AND|OR|XOR|SET) (length 17 bytes):
 155  * Specifies a modification that's done to a received CAN frame before it is
 156  * send out to the destination interface.
 157  *
 158  * <struct can_frame> data used as operator
 159  * <u8> affected CAN frame elements
 160  *
 161  * CGW_LIM_HOPS (length 1 byte):
 162  * Limit the number of hops of this specific rule. Usually the received CAN
 163  * frame can be processed as much as 'max_hops' times (which is given at module
 164  * load time of the can-gw module). This value is used to reduce the number of
 165  * possible hops for this gateway rule to a value smaller then max_hops.
 166  *
 167  * CGW_MOD_UID (length 4 bytes):
 168  * Optional non-zero user defined routing job identifier to alter existing
 169  * modification settings at runtime.
 170  *
 171  * CGW_CS_XOR (length 4 bytes):
 172  * Set a simple XOR checksum starting with an initial value into
 173  * data[result-idx] using data[start-idx] .. data[end-idx]
 174  *
 175  * The XOR checksum is calculated like this:
 176  *
 177  * xor = init_xor_val
 178  *
 179  * for (i = from_idx .. to_idx)
 180  *      xor ^= can_frame.data[i]
 181  *
 182  * can_frame.data[ result_idx ] = xor
 183  *
 184  * CGW_CS_CRC8 (length 282 bytes):
 185  * Set a CRC8 value into data[result-idx] using a given 256 byte CRC8 table,
 186  * a given initial value and a defined input data[start-idx] .. data[end-idx].
 187  * Finally the result value is XOR'ed with the final_xor_val.
 188  *
 189  * The CRC8 checksum is calculated like this:
 190  *
 191  * crc = init_crc_val
 192  *
 193  * for (i = from_idx .. to_idx)
 194  *      crc = crctab[ crc ^ can_frame.data[i] ]
 195  *
 196  * can_frame.data[ result_idx ] = crc ^ final_xor_val
 197  *
 198  * The calculated CRC may contain additional source data elements that can be
 199  * defined in the handling of 'checksum profiles' e.g. shown in AUTOSAR specs
 200  * like http://www.autosar.org/download/R4.0/AUTOSAR_SWS_E2ELibrary.pdf
 201  * E.g. the profile_data[] may contain additional u8 values (called DATA_IDs)
 202  * that are used depending on counter values inside the CAN frame data[].
 203  * So far only three profiles have been implemented for illustration.
 204  *
 205  * Remark: In general the attribute data is a linear buffer.
 206  *         Beware of sending unpacked or aligned structs!
 207  */
 208
 209 #endif /* !_UAPI_CAN_GW_H */