1 /* 2 * linux/can/gw.h 3 * 4 * Definitions for CAN frame Gateway/Router/Bridge 5 * 6 * Author: Oliver Hartkopp <oliver.hartkopp@volkswagen.de> 7 * Copyright (c) 2011 Volkswagen Group Electronic Research 8 * All rights reserved. 9 * 10 */ 11 12 #ifndef CAN_GW_H 13 #define CAN_GW_H 14 15 #include <linux/types.h> 16 #include <linux/can.h> 17 18 struct rtcanmsg { 19 __u8 can_family; 20 __u8 gwtype; 21 __u16 flags; 22 }; 23 24 /* CAN gateway types */ 25 enum { 26 CGW_TYPE_UNSPEC, 27 CGW_TYPE_CAN_CAN, /* CAN->CAN routing */ 28 __CGW_TYPE_MAX 29 }; 30 31 #define CGW_TYPE_MAX (__CGW_TYPE_MAX - 1) 32 33 /* CAN rtnetlink attribute definitions */ 34 enum { 35 CGW_UNSPEC, 36 CGW_MOD_AND, /* CAN frame modification binary AND */ 37 CGW_MOD_OR, /* CAN frame modification binary OR */ 38 CGW_MOD_XOR, /* CAN frame modification binary XOR */ 39 CGW_MOD_SET, /* CAN frame modification set alternate values */ 40 CGW_CS_XOR, /* set data[] XOR checksum into data[index] */ 41 CGW_CS_CRC8, /* set data[] CRC8 checksum into data[index] */ 42 CGW_HANDLED, /* number of handled CAN frames */ 43 CGW_DROPPED, /* number of dropped CAN frames */ 44 CGW_SRC_IF, /* ifindex of source network interface */ 45 CGW_DST_IF, /* ifindex of destination network interface */ 46 CGW_FILTER, /* specify struct can_filter on source CAN device */ 47 CGW_DELETED, /* number of deleted CAN frames (see max_hops param) */ 48 __CGW_MAX 49 }; 50 51 #define CGW_MAX (__CGW_MAX - 1) 52 53 #define CGW_FLAGS_CAN_ECHO 0x01 54 #define CGW_FLAGS_CAN_SRC_TSTAMP 0x02 55 #define CGW_FLAGS_CAN_IIF_TX_OK 0x04 56 57 #define CGW_MOD_FUNCS 4 /* AND OR XOR SET */ 58 59 /* CAN frame elements that are affected by curr. 3 CAN frame modifications */ 60 #define CGW_MOD_ID 0x01 61 #define CGW_MOD_DLC 0x02 62 #define CGW_MOD_DATA 0x04 63 64 #define CGW_FRAME_MODS 3 /* ID DLC DATA */ 65 66 #define MAX_MODFUNCTIONS (CGW_MOD_FUNCS * CGW_FRAME_MODS) 67 68 struct cgw_frame_mod { 69 struct can_frame cf; 70 __u8 modtype; 71 } __attribute__((packed)); 72 73 #define CGW_MODATTR_LEN sizeof(struct cgw_frame_mod) 74 75 struct cgw_csum_xor { 76 __s8 from_idx; 77 __s8 to_idx; 78 __s8 result_idx; 79 __u8 init_xor_val; 80 } __attribute__((packed)); 81 82 struct cgw_csum_crc8 { 83 __s8 from_idx; 84 __s8 to_idx; 85 __s8 result_idx; 86 __u8 init_crc_val; 87 __u8 final_xor_val; 88 __u8 crctab[256]; 89 __u8 profile; 90 __u8 profile_data[20]; 91 } __attribute__((packed)); 92 93 /* length of checksum operation parameters. idx = index in CAN frame data[] */ 94 #define CGW_CS_XOR_LEN sizeof(struct cgw_csum_xor) 95 #define CGW_CS_CRC8_LEN sizeof(struct cgw_csum_crc8) 96 97 /* CRC8 profiles (compute CRC for additional data elements - see below) */ 98 enum { 99 CGW_CRC8PRF_UNSPEC, 100 CGW_CRC8PRF_1U8, /* compute one additional u8 value */ 101 CGW_CRC8PRF_16U8, /* u8 value table indexed by data[1] & 0xF */ 102 CGW_CRC8PRF_SFFID_XOR, /* (can_id & 0xFF) ^ (can_id >> 8 & 0xFF) */ 103 __CGW_CRC8PRF_MAX 104 }; 105 106 #define CGW_CRC8PRF_MAX (__CGW_CRC8PRF_MAX - 1) 107 108 /* 109 * CAN rtnetlink attribute contents in detail 110 * 111 * CGW_XXX_IF (length 4 bytes): 112 * Sets an interface index for source/destination network interfaces. 113 * For the CAN->CAN gwtype the indices of _two_ CAN interfaces are mandatory. 114 * 115 * CGW_FILTER (length 8 bytes): 116 * Sets a CAN receive filter for the gateway job specified by the 117 * struct can_filter described in include/linux/can.h 118 * 119 * CGW_MOD_XXX (length 17 bytes): 120 * Specifies a modification that's done to a received CAN frame before it is 121 * send out to the destination interface. 122 * 123 * <struct can_frame> data used as operator 124 * <u8> affected CAN frame elements 125 * 126 * CGW_CS_XOR (length 4 bytes): 127 * Set a simple XOR checksum starting with an initial value into 128 * data[result-idx] using data[start-idx] .. data[end-idx] 129 * 130 * The XOR checksum is calculated like this: 131 * 132 * xor = init_xor_val 133 * 134 * for (i = from_idx .. to_idx) 135 * xor ^= can_frame.data[i] 136 * 137 * can_frame.data[ result_idx ] = xor 138 * 139 * CGW_CS_CRC8 (length 282 bytes): 140 * Set a CRC8 value into data[result-idx] using a given 256 byte CRC8 table, 141 * a given initial value and a defined input data[start-idx] .. data[end-idx]. 142 * Finally the result value is XOR'ed with the final_xor_val. 143 * 144 * The CRC8 checksum is calculated like this: 145 * 146 * crc = init_crc_val 147 * 148 * for (i = from_idx .. to_idx) 149 * crc = crctab[ crc ^ can_frame.data[i] ] 150 * 151 * can_frame.data[ result_idx ] = crc ^ final_xor_val 152 * 153 * The calculated CRC may contain additional source data elements that can be 154 * defined in the handling of 'checksum profiles' e.g. shown in AUTOSAR specs 155 * like http://www.autosar.org/download/R4.0/AUTOSAR_SWS_E2ELibrary.pdf 156 * E.g. the profile_data[] may contain additional u8 values (called DATA_IDs) 157 * that are used depending on counter values inside the CAN frame data[]. 158 * So far only three profiles have been implemented for illustration. 159 * 160 * Remark: In general the attribute data is a linear buffer. 161 * Beware of sending unpacked or aligned structs! 162 */ 163 164 #endif 165