• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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  * 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 _UAPI_CAN_GW_H
45 #define _UAPI_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_MOD_UID,	/* user defined identifier for modification updates */
82 	__CGW_MAX
83 };
84 
85 #define CGW_MAX (__CGW_MAX - 1)
86 
87 #define CGW_FLAGS_CAN_ECHO 0x01
88 #define CGW_FLAGS_CAN_SRC_TSTAMP 0x02
89 #define CGW_FLAGS_CAN_IIF_TX_OK 0x04
90 
91 #define CGW_MOD_FUNCS 4 /* AND OR XOR SET */
92 
93 /* CAN frame elements that are affected by curr. 3 CAN frame modifications */
94 #define CGW_MOD_ID	0x01
95 #define CGW_MOD_DLC	0x02
96 #define CGW_MOD_DATA	0x04
97 
98 #define CGW_FRAME_MODS 3 /* ID DLC DATA */
99 
100 #define MAX_MODFUNCTIONS (CGW_MOD_FUNCS * CGW_FRAME_MODS)
101 
102 struct cgw_frame_mod {
103 	struct can_frame cf;
104 	__u8 modtype;
105 } __attribute__((packed));
106 
107 #define CGW_MODATTR_LEN sizeof(struct cgw_frame_mod)
108 
109 struct cgw_csum_xor {
110 	__s8 from_idx;
111 	__s8 to_idx;
112 	__s8 result_idx;
113 	__u8 init_xor_val;
114 } __attribute__((packed));
115 
116 struct cgw_csum_crc8 {
117 	__s8 from_idx;
118 	__s8 to_idx;
119 	__s8 result_idx;
120 	__u8 init_crc_val;
121 	__u8 final_xor_val;
122 	__u8 crctab[256];
123 	__u8 profile;
124 	__u8 profile_data[20];
125 } __attribute__((packed));
126 
127 /* length of checksum operation parameters. idx = index in CAN frame data[] */
128 #define CGW_CS_XOR_LEN  sizeof(struct cgw_csum_xor)
129 #define CGW_CS_CRC8_LEN  sizeof(struct cgw_csum_crc8)
130 
131 /* CRC8 profiles (compute CRC for additional data elements - see below) */
132 enum {
133 	CGW_CRC8PRF_UNSPEC,
134 	CGW_CRC8PRF_1U8,	/* compute one additional u8 value */
135 	CGW_CRC8PRF_16U8,	/* u8 value table indexed by data[1] & 0xF */
136 	CGW_CRC8PRF_SFFID_XOR,	/* (can_id & 0xFF) ^ (can_id >> 8 & 0xFF) */
137 	__CGW_CRC8PRF_MAX
138 };
139 
140 #define CGW_CRC8PRF_MAX (__CGW_CRC8PRF_MAX - 1)
141 
142 /*
143  * CAN rtnetlink attribute contents in detail
144  *
145  * CGW_XXX_IF (length 4 bytes):
146  * Sets an interface index for source/destination network interfaces.
147  * For the CAN->CAN gwtype the indices of _two_ CAN interfaces are mandatory.
148  *
149  * CGW_FILTER (length 8 bytes):
150  * Sets a CAN receive filter for the gateway job specified by the
151  * struct can_filter described in include/linux/can.h
152  *
153  * CGW_MOD_(AND|OR|XOR|SET) (length 17 bytes):
154  * Specifies a modification that's done to a received CAN frame before it is
155  * send out to the destination interface.
156  *
157  * <struct can_frame> data used as operator
158  * <u8> affected CAN frame elements
159  *
160  * CGW_LIM_HOPS (length 1 byte):
161  * Limit the number of hops of this specific rule. Usually the received CAN
162  * frame can be processed as much as 'max_hops' times (which is given at module
163  * load time of the can-gw module). This value is used to reduce the number of
164  * possible hops for this gateway rule to a value smaller then max_hops.
165  *
166  * CGW_MOD_UID (length 4 bytes):
167  * Optional non-zero user defined routing job identifier to alter existing
168  * modification settings at runtime.
169  *
170  * CGW_CS_XOR (length 4 bytes):
171  * Set a simple XOR checksum starting with an initial value into
172  * data[result-idx] using data[start-idx] .. data[end-idx]
173  *
174  * The XOR checksum is calculated like this:
175  *
176  * xor = init_xor_val
177  *
178  * for (i = from_idx .. to_idx)
179  *      xor ^= can_frame.data[i]
180  *
181  * can_frame.data[ result_idx ] = xor
182  *
183  * CGW_CS_CRC8 (length 282 bytes):
184  * Set a CRC8 value into data[result-idx] using a given 256 byte CRC8 table,
185  * a given initial value and a defined input data[start-idx] .. data[end-idx].
186  * Finally the result value is XOR'ed with the final_xor_val.
187  *
188  * The CRC8 checksum is calculated like this:
189  *
190  * crc = init_crc_val
191  *
192  * for (i = from_idx .. to_idx)
193  *      crc = crctab[ crc ^ can_frame.data[i] ]
194  *
195  * can_frame.data[ result_idx ] = crc ^ final_xor_val
196  *
197  * The calculated CRC may contain additional source data elements that can be
198  * defined in the handling of 'checksum profiles' e.g. shown in AUTOSAR specs
199  * like http://www.autosar.org/download/R4.0/AUTOSAR_SWS_E2ELibrary.pdf
200  * E.g. the profile_data[] may contain additional u8 values (called DATA_IDs)
201  * that are used depending on counter values inside the CAN frame data[].
202  * So far only three profiles have been implemented for illustration.
203  *
204  * Remark: In general the attribute data is a linear buffer.
205  *         Beware of sending unpacked or aligned structs!
206  */
207 
208 #endif /* !_UAPI_CAN_GW_H */
209