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Edit File: gw.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. * */ #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_DELETED, /* number of deleted CAN frames (see max_hops param) */ __CGW_MAX }; #define CGW_MAX (__CGW_MAX - 1) #define CGW_FLAGS_CAN_ECHO 0x01 #define CGW_FLAGS_CAN_SRC_TSTAMP 0x02 #define CGW_FLAGS_CAN_IIF_TX_OK 0x04 #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