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c1aabdf3 OH |
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 | * | |
c1aabdf3 OH |
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_MAX | |
48 | }; | |
49 | ||
50 | #define CGW_MAX (__CGW_MAX - 1) | |
51 | ||
52 | #define CGW_FLAGS_CAN_ECHO 0x01 | |
53 | #define CGW_FLAGS_CAN_SRC_TSTAMP 0x02 | |
54 | ||
55 | #define CGW_MOD_FUNCS 4 /* AND OR XOR SET */ | |
56 | ||
57 | /* CAN frame elements that are affected by curr. 3 CAN frame modifications */ | |
58 | #define CGW_MOD_ID 0x01 | |
59 | #define CGW_MOD_DLC 0x02 | |
60 | #define CGW_MOD_DATA 0x04 | |
61 | ||
62 | #define CGW_FRAME_MODS 3 /* ID DLC DATA */ | |
63 | ||
64 | #define MAX_MODFUNCTIONS (CGW_MOD_FUNCS * CGW_FRAME_MODS) | |
65 | ||
66 | struct cgw_frame_mod { | |
67 | struct can_frame cf; | |
68 | __u8 modtype; | |
69 | } __attribute__((packed)); | |
70 | ||
71 | #define CGW_MODATTR_LEN sizeof(struct cgw_frame_mod) | |
72 | ||
73 | struct cgw_csum_xor { | |
74 | __s8 from_idx; | |
75 | __s8 to_idx; | |
76 | __s8 result_idx; | |
77 | __u8 init_xor_val; | |
78 | } __attribute__((packed)); | |
79 | ||
80 | struct cgw_csum_crc8 { | |
81 | __s8 from_idx; | |
82 | __s8 to_idx; | |
83 | __s8 result_idx; | |
84 | __u8 init_crc_val; | |
85 | __u8 final_xor_val; | |
86 | __u8 crctab[256]; | |
87 | __u8 profile; | |
88 | __u8 profile_data[20]; | |
89 | } __attribute__((packed)); | |
90 | ||
91 | /* length of checksum operation parameters. idx = index in CAN frame data[] */ | |
92 | #define CGW_CS_XOR_LEN sizeof(struct cgw_csum_xor) | |
93 | #define CGW_CS_CRC8_LEN sizeof(struct cgw_csum_crc8) | |
94 | ||
95 | /* CRC8 profiles (compute CRC for additional data elements - see below) */ | |
96 | enum { | |
97 | CGW_CRC8PRF_UNSPEC, | |
98 | CGW_CRC8PRF_1U8, /* compute one additional u8 value */ | |
99 | CGW_CRC8PRF_16U8, /* u8 value table indexed by data[1] & 0xF */ | |
100 | CGW_CRC8PRF_SFFID_XOR, /* (can_id & 0xFF) ^ (can_id >> 8 & 0xFF) */ | |
101 | __CGW_CRC8PRF_MAX | |
102 | }; | |
103 | ||
104 | #define CGW_CRC8PRF_MAX (__CGW_CRC8PRF_MAX - 1) | |
105 | ||
106 | /* | |
107 | * CAN rtnetlink attribute contents in detail | |
108 | * | |
109 | * CGW_XXX_IF (length 4 bytes): | |
110 | * Sets an interface index for source/destination network interfaces. | |
111 | * For the CAN->CAN gwtype the indices of _two_ CAN interfaces are mandatory. | |
112 | * | |
113 | * CGW_FILTER (length 8 bytes): | |
114 | * Sets a CAN receive filter for the gateway job specified by the | |
115 | * struct can_filter described in include/linux/can.h | |
116 | * | |
117 | * CGW_MOD_XXX (length 17 bytes): | |
118 | * Specifies a modification that's done to a received CAN frame before it is | |
119 | * send out to the destination interface. | |
120 | * | |
121 | * <struct can_frame> data used as operator | |
122 | * <u8> affected CAN frame elements | |
123 | * | |
124 | * CGW_CS_XOR (length 4 bytes): | |
125 | * Set a simple XOR checksum starting with an initial value into | |
126 | * data[result-idx] using data[start-idx] .. data[end-idx] | |
127 | * | |
128 | * The XOR checksum is calculated like this: | |
129 | * | |
130 | * xor = init_xor_val | |
131 | * | |
132 | * for (i = from_idx .. to_idx) | |
133 | * xor ^= can_frame.data[i] | |
134 | * | |
135 | * can_frame.data[ result_idx ] = xor | |
136 | * | |
137 | * CGW_CS_CRC8 (length 282 bytes): | |
138 | * Set a CRC8 value into data[result-idx] using a given 256 byte CRC8 table, | |
139 | * a given initial value and a defined input data[start-idx] .. data[end-idx]. | |
140 | * Finally the result value is XOR'ed with the final_xor_val. | |
141 | * | |
142 | * The CRC8 checksum is calculated like this: | |
143 | * | |
144 | * crc = init_crc_val | |
145 | * | |
146 | * for (i = from_idx .. to_idx) | |
147 | * crc = crctab[ crc ^ can_frame.data[i] ] | |
148 | * | |
149 | * can_frame.data[ result_idx ] = crc ^ final_xor_val | |
150 | * | |
151 | * The calculated CRC may contain additional source data elements that can be | |
152 | * defined in the handling of 'checksum profiles' e.g. shown in AUTOSAR specs | |
153 | * like http://www.autosar.org/download/R4.0/AUTOSAR_SWS_E2ELibrary.pdf | |
154 | * E.g. the profile_data[] may contain additional u8 values (called DATA_IDs) | |
155 | * that are used depending on counter values inside the CAN frame data[]. | |
156 | * So far only three profiles have been implemented for illustration. | |
157 | * | |
158 | * Remark: In general the attribute data is a linear buffer. | |
159 | * Beware of sending unpacked or aligned structs! | |
160 | */ | |
161 | ||
162 | #endif |