diff options
Diffstat (limited to 'include/linux/can/gw.h')
| -rw-r--r-- | include/linux/can/gw.h | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/include/linux/can/gw.h b/include/linux/can/gw.h new file mode 100644 index 00000000..8e1db18c --- /dev/null +++ b/include/linux/can/gw.h @@ -0,0 +1,162 @@ +/* + * 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_MAX +}; + +#define CGW_MAX (__CGW_MAX - 1) + +#define CGW_FLAGS_CAN_ECHO 0x01 +#define CGW_FLAGS_CAN_SRC_TSTAMP 0x02 + +#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 |