xref: /linux/include/uapi/linux/can/gw.h (revision cdd38c5f1ce4398ec58fec95904b75824daab7b5)
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		/* Classical CAN data length code */
102 #define CGW_MOD_LEN	CGW_MOD_DLC	/* CAN FD (plain) data length */
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 */
223