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cvs.zerfleddert.de Git - proxmark3-svn/blob - common/crc.c
2f11f5f45f6c97386ffb6a595b014b05bd7a3e3b
1 //-----------------------------------------------------------------------------
2 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
3 // at your option, any later version. See the LICENSE.txt file for the text of
5 //-----------------------------------------------------------------------------
6 // Generic CRC calculation code.
7 //-----------------------------------------------------------------------------
8 // the Check value below in the comments is CRC of the string '123456789'
12 void crc_init_ref(crc_t
*crc
, int order
, uint32_t polynom
, uint32_t initial_value
, uint32_t final_xor
, bool refin
, bool refout
) {
13 crc_init(crc
, order
, polynom
, initial_value
, final_xor
);
19 void crc_init(crc_t
*crc
, int order
, uint32_t polynom
, uint32_t initial_value
, uint32_t final_xor
) {
21 crc
->topbit
= BITMASK( order
-1 );
22 crc
->polynom
= polynom
;
23 crc
->initial_value
= initial_value
;
24 crc
->final_xor
= final_xor
;
25 crc
->mask
= (1L<<order
)-1;
31 void crc_clear(crc_t
*crc
) {
32 crc
->state
= crc
->initial_value
& crc
->mask
;
34 crc
->state
= reflect(crc
->state
, crc
->order
);
37 void crc_update(crc_t
*crc
, uint32_t indata
, int data_width
){
40 if (crc
->refin
) indata
= reflect(indata
, data_width
);
42 // Bring the next byte into the remainder.
43 crc
->state
^= indata
<< (crc
->order
- data_width
);
45 for( uint8_t bit
= data_width
; bit
> 0; --bit
) {
48 // Try to divide the current data bit.
49 if (crc
->state
& crc
->topbit
)
50 crc
->state
= (crc
->state
<< 1) ^ crc
->polynom
;
52 crc
->state
= (crc
->state
<< 1);
56 void crc_update2(crc_t
*crc
, uint32_t data
, int data_width
)
58 if (crc
->refin
) data
= reflect(data
, data_width
);
61 for(i
=0; i
<data_width
; i
++) {
62 int oldstate
= crc
->state
;
63 crc
->state
= crc
->state
>> 1;
64 if( (oldstate
^data
) & 1 ) {
65 crc
->state
^= crc
->polynom
;
72 uint32_t crc_finish(crc_t
*crc
) {
73 uint32_t val
= crc
->state
;
74 if (crc
->refout
) val
= reflect(val
, crc
->order
);
75 return ( val
^ crc
->final_xor
) & crc
->mask
;
79 static void print_crc(crc_t *crc) {
80 printf(" Order %d\n Poly %x\n Init %x\n Final %x\n Mask %x\n topbit %x\n RefIn %s\n RefOut %s\n State %x\n",
87 (crc->refin) ? "TRUE":"FALSE",
88 (crc->refout) ? "TRUE":"FALSE",
94 // width=8 poly=0x31 init=0x00 refin=true refout=true xorout=0x00 check=0xA1 name="CRC-8/MAXIM"
95 uint32_t CRC8Maxim(uint8_t *buff
, size_t size
) {
97 crc_init_ref(&crc
, 8, 0x31, 0, 0, TRUE
, TRUE
);
98 for ( int i
=0; i
< size
; ++i
)
99 crc_update(&crc
, buff
[i
], 8);
100 return crc_finish(&crc
);
103 // width=4 poly=0xC, reversed poly=0x7 init=0x5 refin=true refout=true xorout=0x0000 check= name="CRC-4/LEGIC"
104 uint32_t CRC4Legic(uint8_t *cmd
, size_t size
) {
106 crc_init_ref(&crc
, 4, 0x19 >> 1, 0x5, 0, TRUE
, TRUE
);
107 crc_update2(&crc
, 1, 1); /* CMD_READ */
108 crc_update2(&crc
, cmd
[0], 8);
109 crc_update2(&crc
, cmd
[1], 8);
110 return reflect(crc_finish(&crc
), 4);
112 // width=8 poly=0x63, reversed poly=0x8D init=0x55 refin=true refout=true xorout=0x0000 check=0xC6 name="CRC-8/LEGIC"
113 // the CRC needs to be reversed before returned.
114 uint32_t CRC8Legic(uint8_t *buff
, size_t size
) {
116 crc_init_ref(&crc
, 8, 0x63, 0x55, 0, TRUE
, TRUE
);
117 for ( int i
= 0; i
< size
; ++i
)
118 crc_update(&crc
, buff
[i
], 8);
119 return reflect(crc_finish(&crc
), 8);
122 // This CRC-16 is used in Legic Advant systems.
123 // width=8 poly=0xB400, reversed poly=0x init=depends refin=true refout=true xorout=0x0000 check= name="CRC-16/LEGIC"
124 uint32_t CRC16Legic(uint8_t *buff
, size_t size
, uint8_t uidcrc
) {
126 #define CRC16_POLY_LEGIC 0xB400
127 uint16_t initial
= reflect(uidcrc
, 8);
128 //uint16_t initial = uidcrc;
129 initial
|= initial
<< 8;
131 crc_init_ref(&crc
, 16, CRC16_POLY_LEGIC
, initial
, 0, TRUE
, TRUE
);
132 for ( int i
=0; i
< size
; ++i
)
133 crc_update(&crc
, buff
[i
], 8);
134 return reflect(crc_finish(&crc
), 16);
137 //w=16 poly=0x3d65 init=0x0000 refin=true refout=true xorout=0xffff check=0xea82 name="CRC-16/DNP"
138 uint32_t CRC16_DNP(uint8_t *buff
, size_t size
) {
140 crc_init_ref(&crc
, 16, 0x3d65, 0, 0xffff, TRUE
, TRUE
);
141 for ( int i
=0; i
< size
; ++i
)
142 crc_update(&crc
, buff
[i
], 8);
144 return BSWAP_16(crc_finish(&crc
));
147 //width=16 poly=0x1021 init=0x1d0f refin=false refout=false xorout=0x0000 check=0xe5cc name="CRC-16/AUG-CCITT"
148 uint32_t CRC16_CCITT(uint8_t *buff
, size_t size
) {
150 crc_init(&crc
, 16, 0x1021, 0x1d0f, 0);
151 for ( int i
=0; i
< size
; ++i
)
152 crc_update(&crc
, buff
[i
], 8);
153 return crc_finish(&crc
);
155 //width=16 poly=0x8408 init=0xffff refin=false refout=true xorout=0xffff check=0xF0B8 name="CRC-16/ISO/IEC 13239"
156 uint32_t CRC16_Iso15693(uint8_t *buff
, size_t size
) {
158 crc_init_ref(&crc
, 16, 0x8408, 0xFFFF, 0xFFFF, true, false);
159 for ( int i
=0; i
< size
; ++i
)
160 crc_update(&crc
, buff
[i
], 8);
161 return reflect(crc_finish(&crc
), 16);
163 //width=16 poly=0x8408 init=0xffff refin=true refout=true xorout=0x0BC3 check=0xF0B8 name="CRC-16/ICLASS"
164 uint32_t CRC16_ICLASS(uint8_t *buff
, size_t size
) {
167 crc_init_ref(&crc
, 16, 0x8408, 0xFFFF, 0x0BC3, false, false);
168 for ( int i
=0; i
< size
; ++i
)
169 crc_update(&crc
, buff
[i
], 8);
170 return crc_finish(&crc
);