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 */ 210
