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