2 * lib/crypto/crc32/crc.c
4 * Copyright 1990 by the Massachusetts Institute of Technology.
7 * Export of this software from the United States of America may
8 * require a specific license from the United States Government.
9 * It is the responsibility of any person or organization contemplating
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12 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
13 * distribute this software and its documentation for any purpose and
14 * without fee is hereby granted, provided that the above copyright
15 * notice appear in all copies and that both that copyright notice and
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17 * the name of M.I.T. not be used in advertising or publicity pertaining
18 * to distribution of the software without specific, written prior
19 * permission. M.I.T. makes no representations about the suitability of
20 * this software for any purpose. It is provided "as is" without express
21 * or implied warranty.
24 * CRC-32/AUTODIN-II routines
28 #include <krb5/krb5.h>
29 #include <krb5/crc-32.h>
30 #include <krb5/ext-proto.h>
32 /* This table and block of comments are taken from code labeled: */
34 * Copyright (C) 1986 Gary S. Brown. You may use this program, or
35 * code or tables extracted from it, as desired without restriction.
38 /* First, the polynomial itself and its table of feedback terms. The */
40 /* X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0 */
41 /* Note that we take it "backwards" and put the highest-order term in */
42 /* the lowest-order bit. The X^32 term is "implied"; the LSB is the */
43 /* X^31 term, etc. The X^0 term (usually shown as "+1") results in */
44 /* the MSB being 1. */
46 /* Note that the usual hardware shift register implementation, which */
47 /* is what we're using (we're merely optimizing it by doing eight-bit */
48 /* chunks at a time) shifts bits into the lowest-order term. In our */
49 /* implementation, that means shifting towards the right. Why do we */
50 /* do it this way? Because the calculated CRC must be transmitted in */
51 /* order from highest-order term to lowest-order term. UARTs transmit */
52 /* characters in order from LSB to MSB. By storing the CRC this way, */
53 /* we hand it to the UART in the order low-byte to high-byte; the UART */
54 /* sends each low-bit to hight-bit; and the result is transmission bit */
55 /* by bit from highest- to lowest-order term without requiring any bit */
56 /* shuffling on our part. Reception works similarly. */
58 /* The feedback terms table consists of 256, 32-bit entries. Notes: */
60 /* 1. The table can be generated at runtime if desired; code to do so */
61 /* is shown later. It might not be obvious, but the feedback */
62 /* terms simply represent the results of eight shift/xor opera- */
63 /* tions for all combinations of data and CRC register values. */
65 /* 2. The CRC accumulation logic is the same for all CRC polynomials, */
66 /* be they sixteen or thirty-two bits wide. You simply choose the */
67 /* appropriate table. Alternatively, because the table can be */
68 /* generated at runtime, you can start by generating the table for */
69 /* the polynomial in question and use exactly the same "updcrc", */
70 /* if your application needn't simultaneously handle two CRC */
71 /* polynomials. (Note, however, that XMODEM is strange.) */
73 /* 3. For 16-bit CRCs, the table entries need be only 16 bits wide; */
74 /* of course, 32-bit entries work OK if the high 16 bits are zero. */
76 /* 4. The values must be right-shifted by eight bits by the "updcrc" */
77 /* logic; the shift must be unsigned (bring in zeroes). On some */
78 /* hardware you could probably optimize the shift in assembler by */
79 /* using byte-swap instructions. */
81 static u_long const crc_table[256] = {
82 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
83 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
84 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
85 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
86 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
87 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
88 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
89 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
90 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
91 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
92 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
93 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
94 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
95 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
96 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
97 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
98 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
99 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
100 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
101 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
102 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
103 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
104 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
105 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
106 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
107 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
108 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
109 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
110 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
111 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
112 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
113 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
114 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
115 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
116 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
117 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
118 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
119 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
120 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
121 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
122 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
123 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
124 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
125 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
126 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
127 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
128 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
129 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
130 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
131 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
132 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
133 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
134 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
135 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
136 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
137 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
138 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
139 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
140 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
141 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
142 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
143 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
144 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
145 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
148 static krb5_error_code
149 crc32_sum_func(in, in_length, seed, seed_length, outcksum)
154 krb5_checksum *outcksum;
156 register u_char *data;
157 register u_long c = 0;
162 for (i=0; i<in_length;i++) {
168 /* c now holds the result */
169 outcksum->checksum_type = CKSUMTYPE_CRC32;
170 outcksum->length = 4;
171 outcksum->contents[0] = c & 0xff;
172 outcksum->contents[1] = (c >> 8) & 0xff;
173 outcksum->contents[2] = (c >> 16) & 0xff;
174 outcksum->contents[3] = (c >> 24) & 0xff;
179 krb5_checksum_entry crc32_cksumtable_entry = {
181 CRC32_CKSUM_LENGTH, /* CRC-32 is 4 octets */
182 0, /* not collision proof */
183 0, /* doesn't use key */