1 /* SPDX-License-Identifier: ((GPL-2.0-only WITH Linux-syscall-note) OR BSD-3-Clause) */
2 /*
3 * linux/can/gw.h
4 *
5 * Definitions for CAN frame Gateway/Router/Bridge
6 *
7 * Author: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
8 * Copyright (c) 2011 Volkswagen Group Electronic Research
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. Neither the name of Volkswagen nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * Alternatively, provided that this notice is retained in full, this
24 * software may be distributed under the terms of the GNU General
25 * Public License ("GPL") version 2, in which case the provisions of the
26 * GPL apply INSTEAD OF those given above.
27 *
28 * The provided data structures and external interfaces from this code
29 * are not restricted to be used by modules with a GPL compatible license.
30 *
31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
34 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
36 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
37 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
38 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
39 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
40 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
41 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
42 * DAMAGE.
43 */
44
45 #ifndef _UAPI_CAN_GW_H
46 #define _UAPI_CAN_GW_H
47
48 #include <linux/types.h>
49 #include <linux/can.h>
50
51 struct rtcanmsg {
52 __u8 can_family;
53 __u8 gwtype;
54 __u16 flags;
55 };
56
57 /* CAN gateway types */
58 enum {
59 CGW_TYPE_UNSPEC,
60 CGW_TYPE_CAN_CAN, /* CAN->CAN routing */
61 __CGW_TYPE_MAX
62 };
63
64 #define CGW_TYPE_MAX (__CGW_TYPE_MAX - 1)
65
66 /* CAN rtnetlink attribute definitions */
67 enum {
68 CGW_UNSPEC,
69 CGW_MOD_AND, /* CAN frame modification binary AND */
70 CGW_MOD_OR, /* CAN frame modification binary OR */
71 CGW_MOD_XOR, /* CAN frame modification binary XOR */
72 CGW_MOD_SET, /* CAN frame modification set alternate values */
73 CGW_CS_XOR, /* set data[] XOR checksum into data[index] */
74 CGW_CS_CRC8, /* set data[] CRC8 checksum into data[index] */
75 CGW_HANDLED, /* number of handled CAN frames */
76 CGW_DROPPED, /* number of dropped CAN frames */
77 CGW_SRC_IF, /* ifindex of source network interface */
78 CGW_DST_IF, /* ifindex of destination network interface */
79 CGW_FILTER, /* specify struct can_filter on source CAN device */
80 CGW_DELETED, /* number of deleted CAN frames (see max_hops param) */
81 CGW_LIM_HOPS, /* limit the number of hops of this specific rule */
82 CGW_MOD_UID, /* user defined identifier for modification updates */
83 CGW_FDMOD_AND, /* CAN FD frame modification binary AND */
84 CGW_FDMOD_OR, /* CAN FD frame modification binary OR */
85 CGW_FDMOD_XOR, /* CAN FD frame modification binary XOR */
86 CGW_FDMOD_SET, /* CAN FD frame modification set alternate values */
87 __CGW_MAX
88 };
89
90 #define CGW_MAX (__CGW_MAX - 1)
91
92 #define CGW_FLAGS_CAN_ECHO 0x01
93 #define CGW_FLAGS_CAN_SRC_TSTAMP 0x02
94 #define CGW_FLAGS_CAN_IIF_TX_OK 0x04
95 #define CGW_FLAGS_CAN_FD 0x08
96
97 #define CGW_MOD_FUNCS 4 /* AND OR XOR SET */
98
99 /* CAN frame elements that are affected by curr. 3 CAN frame modifications */
100 #define CGW_MOD_ID 0x01
101 #define CGW_MOD_DLC 0x02 /* contains the data length in bytes */
102 #define CGW_MOD_LEN CGW_MOD_DLC /* CAN FD length representation */
103 #define CGW_MOD_DATA 0x04
104 #define CGW_MOD_FLAGS 0x08 /* CAN FD flags */
105
106 #define CGW_FRAME_MODS 4 /* ID DLC/LEN DATA FLAGS */
107
108 #define MAX_MODFUNCTIONS (CGW_MOD_FUNCS * CGW_FRAME_MODS)
109
110 struct cgw_frame_mod {
111 struct can_frame cf;
112 __u8 modtype;
113 } __attribute__((packed));
114
115 struct cgw_fdframe_mod {
116 struct canfd_frame cf;
117 __u8 modtype;
118 } __attribute__((packed));
119
120 #define CGW_MODATTR_LEN sizeof(struct cgw_frame_mod)
121 #define CGW_FDMODATTR_LEN sizeof(struct cgw_fdframe_mod)
122
123 struct cgw_csum_xor {
124 __s8 from_idx;
125 __s8 to_idx;
126 __s8 result_idx;
127 __u8 init_xor_val;
128 } __attribute__((packed));
129
130 struct cgw_csum_crc8 {
131 __s8 from_idx;
132 __s8 to_idx;
133 __s8 result_idx;
134 __u8 init_crc_val;
135 __u8 final_xor_val;
136 __u8 crctab[256];
137 __u8 profile;
138 __u8 profile_data[20];
139 } __attribute__((packed));
140
141 /* length of checksum operation parameters. idx = index in CAN frame data[] */
142 #define CGW_CS_XOR_LEN sizeof(struct cgw_csum_xor)
143 #define CGW_CS_CRC8_LEN sizeof(struct cgw_csum_crc8)
144
145 /* CRC8 profiles (compute CRC for additional data elements - see below) */
146 enum {
147 CGW_CRC8PRF_UNSPEC,
148 CGW_CRC8PRF_1U8, /* compute one additional u8 value */
149 CGW_CRC8PRF_16U8, /* u8 value table indexed by data[1] & 0xF */
150 CGW_CRC8PRF_SFFID_XOR, /* (can_id & 0xFF) ^ (can_id >> 8 & 0xFF) */
151 __CGW_CRC8PRF_MAX
152 };
153
154 #define CGW_CRC8PRF_MAX (__CGW_CRC8PRF_MAX - 1)
155
156 /*
157 * CAN rtnetlink attribute contents in detail
158 *
159 * CGW_XXX_IF (length 4 bytes):
160 * Sets an interface index for source/destination network interfaces.
161 * For the CAN->CAN gwtype the indices of _two_ CAN interfaces are mandatory.
162 *
163 * CGW_FILTER (length 8 bytes):
164 * Sets a CAN receive filter for the gateway job specified by the
165 * struct can_filter described in include/linux/can.h
166 *
167 * CGW_MOD_(AND|OR|XOR|SET) (length 17 bytes):
168 * Specifies a modification that's done to a received CAN frame before it is
169 * send out to the destination interface.
170 *
171 * <struct can_frame> data used as operator
172 * <u8> affected CAN frame elements
173 *
174 * CGW_LIM_HOPS (length 1 byte):
175 * Limit the number of hops of this specific rule. Usually the received CAN
176 * frame can be processed as much as 'max_hops' times (which is given at module
177 * load time of the can-gw module). This value is used to reduce the number of
178 * possible hops for this gateway rule to a value smaller then max_hops.
179 *
180 * CGW_MOD_UID (length 4 bytes):
181 * Optional non-zero user defined routing job identifier to alter existing
182 * modification settings at runtime.
183 *
184 * CGW_CS_XOR (length 4 bytes):
185 * Set a simple XOR checksum starting with an initial value into
186 * data[result-idx] using data[start-idx] .. data[end-idx]
187 *
188 * The XOR checksum is calculated like this:
189 *
190 * xor = init_xor_val
191 *
192 * for (i = from_idx .. to_idx)
193 * xor ^= can_frame.data[i]
194 *
195 * can_frame.data[ result_idx ] = xor
196 *
197 * CGW_CS_CRC8 (length 282 bytes):
198 * Set a CRC8 value into data[result-idx] using a given 256 byte CRC8 table,
199 * a given initial value and a defined input data[start-idx] .. data[end-idx].
200 * Finally the result value is XOR'ed with the final_xor_val.
201 *
202 * The CRC8 checksum is calculated like this:
203 *
204 * crc = init_crc_val
205 *
206 * for (i = from_idx .. to_idx)
207 * crc = crctab[ crc ^ can_frame.data[i] ]
208 *
209 * can_frame.data[ result_idx ] = crc ^ final_xor_val
210 *
211 * The calculated CRC may contain additional source data elements that can be
212 * defined in the handling of 'checksum profiles' e.g. shown in AUTOSAR specs
213 * like http://www.autosar.org/download/R4.0/AUTOSAR_SWS_E2ELibrary.pdf
214 * E.g. the profile_data[] may contain additional u8 values (called DATA_IDs)
215 * that are used depending on counter values inside the CAN frame data[].
216 * So far only three profiles have been implemented for illustration.
217 *
218 * Remark: In general the attribute data is a linear buffer.
219 * Beware of sending unpacked or aligned structs!
220 */
221
222 #endif /* !_UAPI_CAN_GW_H */