xref: /illumos-gate/usr/src/uts/common/sys/crc32.h (revision 7c478bd9)
1*7c478bd9Sstevel@tonic-gate /*
2*7c478bd9Sstevel@tonic-gate  * CDDL HEADER START
3*7c478bd9Sstevel@tonic-gate  *
4*7c478bd9Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*7c478bd9Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*7c478bd9Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*7c478bd9Sstevel@tonic-gate  * with the License.
8*7c478bd9Sstevel@tonic-gate  *
9*7c478bd9Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*7c478bd9Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*7c478bd9Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*7c478bd9Sstevel@tonic-gate  * and limitations under the License.
13*7c478bd9Sstevel@tonic-gate  *
14*7c478bd9Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*7c478bd9Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*7c478bd9Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*7c478bd9Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*7c478bd9Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*7c478bd9Sstevel@tonic-gate  *
20*7c478bd9Sstevel@tonic-gate  * CDDL HEADER END
21*7c478bd9Sstevel@tonic-gate  */
22*7c478bd9Sstevel@tonic-gate /*
23*7c478bd9Sstevel@tonic-gate  * Copyright 2002 Sun Microsystems, Inc.  All rights reserved.
24*7c478bd9Sstevel@tonic-gate  * Use is subject to license terms.
25*7c478bd9Sstevel@tonic-gate  */
27*7c478bd9Sstevel@tonic-gate #ifndef _SYS_CRC32_H
28*7c478bd9Sstevel@tonic-gate #define	_SYS_CRC32_H
30*7c478bd9Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
32*7c478bd9Sstevel@tonic-gate /*
33*7c478bd9Sstevel@tonic-gate  * CRC32, the 32-bit Cyclic Redundancy Check, is a well-known way to
34*7c478bd9Sstevel@tonic-gate  * generate checksums or hashes.  Extensive literature on the theory
35*7c478bd9Sstevel@tonic-gate  * behind CRC is available on the web; we won't recapitulate it here.
36*7c478bd9Sstevel@tonic-gate  * We must, however, cover a few basics to explain the services we're
37*7c478bd9Sstevel@tonic-gate  * providing.
38*7c478bd9Sstevel@tonic-gate  *
39*7c478bd9Sstevel@tonic-gate  * A CRC function is defined by two parameters: an initial value and a
40*7c478bd9Sstevel@tonic-gate  * 32-bit integer that encodes its generating polynomial (explained later).
41*7c478bd9Sstevel@tonic-gate  * Given these values, the CRC of any bitstream is defined as follows:
42*7c478bd9Sstevel@tonic-gate  *
43*7c478bd9Sstevel@tonic-gate  *	crc = CRC32_INITIAL;
44*7c478bd9Sstevel@tonic-gate  *	foreach (bit of data)
45*7c478bd9Sstevel@tonic-gate  *		if (bit == (crc & 1))
46*7c478bd9Sstevel@tonic-gate  *			crc = (crc >> 1);
47*7c478bd9Sstevel@tonic-gate  *		else
48*7c478bd9Sstevel@tonic-gate  *			crc = (crc >> 1) ^ CRC32_POLY;
49*7c478bd9Sstevel@tonic-gate  *
50*7c478bd9Sstevel@tonic-gate  * That's it.  The algorithm is both simple and surprisingly powerful:
51*7c478bd9Sstevel@tonic-gate  * CRC32 has been proven to detect all single-bit errors, all double-bit
52*7c478bd9Sstevel@tonic-gate  * errors, and all burst errors up to 32 bits long.
53*7c478bd9Sstevel@tonic-gate  *
54*7c478bd9Sstevel@tonic-gate  * The most common values for the CRC parameters are:
55*7c478bd9Sstevel@tonic-gate  *
56*7c478bd9Sstevel@tonic-gate  *	CRC32_INITIAL:	0 or -1
57*7c478bd9Sstevel@tonic-gate  *	CRC32_POLY	0xEDB88320
58*7c478bd9Sstevel@tonic-gate  *
59*7c478bd9Sstevel@tonic-gate  * There is no particular constraint on the initial value; any will yield a
60*7c478bd9Sstevel@tonic-gate  * valid CRC.  (OK, then why not always use zero?  Because CRC was originally
61*7c478bd9Sstevel@tonic-gate  * designed for serial transmission, in which one common form of error
62*7c478bd9Sstevel@tonic-gate  * was a burst of zeroes.  Note that if crc == 0, and we fold in a zero bit,
63*7c478bd9Sstevel@tonic-gate  * we still have crc == 0.  Therefore, if the CRC's initial value is zero,
64*7c478bd9Sstevel@tonic-gate  * an arbitrarily long run of zeroes can be prepended to a packet without
65*7c478bd9Sstevel@tonic-gate  * being detected.)
66*7c478bd9Sstevel@tonic-gate  *
67*7c478bd9Sstevel@tonic-gate  * The constraint on the polynomial is that it must be of degree 32
68*7c478bd9Sstevel@tonic-gate  * and must be primitive in the Galois field of polynomials modulo 2.
69*7c478bd9Sstevel@tonic-gate  * Any such polynomial will yield a valid CRC.  There's no particular
70*7c478bd9Sstevel@tonic-gate  * advantage to one such polynomial over another, so the world has
71*7c478bd9Sstevel@tonic-gate  * largely standardized on a particular one, 0xEDB88320.  [The nth bit
72*7c478bd9Sstevel@tonic-gate  * of this integer is the coefficient of x^n; the coefficient of x^32
73*7c478bd9Sstevel@tonic-gate  * is implicitly 1.]
74*7c478bd9Sstevel@tonic-gate  *
75*7c478bd9Sstevel@tonic-gate  * Of course, we rarely process data bitwise in software.  When processing
76*7c478bd9Sstevel@tonic-gate  * data bytewise, the following calculation is equivalent to the bitwise one:
77*7c478bd9Sstevel@tonic-gate  *
78*7c478bd9Sstevel@tonic-gate  *	crc = CRC32_INITIAL;
79*7c478bd9Sstevel@tonic-gate  *	foreach (byte of data)
80*7c478bd9Sstevel@tonic-gate  *		for (crc ^= byte, i = 8; i > 0; i--)
81*7c478bd9Sstevel@tonic-gate  *			crc = (crc >> 1) ^ (-(crc & 1) & CRC32_POLY);
82*7c478bd9Sstevel@tonic-gate  *
83*7c478bd9Sstevel@tonic-gate  * Note that we still have a bitwise loop in there.  We can avoid this
84*7c478bd9Sstevel@tonic-gate  * by precomputing the CRC of each possible byte [i.e. 0-255] using the
85*7c478bd9Sstevel@tonic-gate  * algorithm above and storing the results in a lookup table.  Given
86*7c478bd9Sstevel@tonic-gate  * such a table, the CRC can be computed quite efficiently as follows:
87*7c478bd9Sstevel@tonic-gate  *
88*7c478bd9Sstevel@tonic-gate  *	crc = CRC32_INITIAL;
89*7c478bd9Sstevel@tonic-gate  *	foreach (byte of data)
90*7c478bd9Sstevel@tonic-gate  *		crc = (crc >> 8) ^ crc32_table[(crc ^ byte) & 0xFF];
91*7c478bd9Sstevel@tonic-gate  *
92*7c478bd9Sstevel@tonic-gate  * The macros below support this form of CRC computation.
93*7c478bd9Sstevel@tonic-gate  *
94*7c478bd9Sstevel@tonic-gate  * We also define a pre-computed crc32_table[] for the polynomial 0xEDB88320.
95*7c478bd9Sstevel@tonic-gate  * This is the only CRC polynomial we actually use in Solaris.
96*7c478bd9Sstevel@tonic-gate  */
98*7c478bd9Sstevel@tonic-gate #ifdef __cplusplus
99*7c478bd9Sstevel@tonic-gate extern "C" {
100*7c478bd9Sstevel@tonic-gate #endif
102*7c478bd9Sstevel@tonic-gate #include <sys/types.h>
104*7c478bd9Sstevel@tonic-gate /*
105*7c478bd9Sstevel@tonic-gate  * Initialize a CRC table [256 uint32_t's] with the given polynomial.
106*7c478bd9Sstevel@tonic-gate  */
107*7c478bd9Sstevel@tonic-gate #define	CRC32_INIT(table, poly)						\
108*7c478bd9Sstevel@tonic-gate {									\
109*7c478bd9Sstevel@tonic-gate 	uint32_t Xi, Xj, *Xt;						\
110*7c478bd9Sstevel@tonic-gate 	for (Xi = 0; Xi < 256; Xi++)					\
111*7c478bd9Sstevel@tonic-gate 		for (Xt = (table) + Xi, *Xt = Xi, Xj = 8; Xj > 0; Xj--)	\
112*7c478bd9Sstevel@tonic-gate 			*Xt = (*Xt >> 1) ^ (-(*Xt & 1) & (poly));	\
113*7c478bd9Sstevel@tonic-gate }
115*7c478bd9Sstevel@tonic-gate /*
116*7c478bd9Sstevel@tonic-gate  * Compute a 32-bit CRC using the specified starting value and table.
117*7c478bd9Sstevel@tonic-gate  * Typical usage: CRC32(crc, buf, size, -1U, crc32_table).
118*7c478bd9Sstevel@tonic-gate  */
119*7c478bd9Sstevel@tonic-gate #define	CRC32(crc, buf, size, start, table)				\
120*7c478bd9Sstevel@tonic-gate {									\
121*7c478bd9Sstevel@tonic-gate 	uint32_t Xcrc = start;						\
122*7c478bd9Sstevel@tonic-gate 	const uint8_t *Xcp = (const uint8_t *)(buf);			\
123*7c478bd9Sstevel@tonic-gate 	const uint8_t *Xcpend = Xcp + (size);				\
124*7c478bd9Sstevel@tonic-gate 	while (Xcp < Xcpend)						\
125*7c478bd9Sstevel@tonic-gate 		Xcrc = (Xcrc >> 8) ^ (table)[(Xcrc ^ *Xcp++) & 0xFF];	\
126*7c478bd9Sstevel@tonic-gate 	crc = Xcrc;							\
127*7c478bd9Sstevel@tonic-gate }
129*7c478bd9Sstevel@tonic-gate /*
130*7c478bd9Sstevel@tonic-gate  * As above, but operate on a null-terminated string instead of an
131*7c478bd9Sstevel@tonic-gate  * array of known size.  Computes both the crc and the string length.
132*7c478bd9Sstevel@tonic-gate  * Typical usage: CRC32_STRING(crc, len, str, -1U, crc32_table).
133*7c478bd9Sstevel@tonic-gate  */
134*7c478bd9Sstevel@tonic-gate #define	CRC32_STRING(crc, len, str, start, table)			\
135*7c478bd9Sstevel@tonic-gate {									\
136*7c478bd9Sstevel@tonic-gate 	uint32_t Xcrc = start;						\
137*7c478bd9Sstevel@tonic-gate 	const uint8_t *Xcp;						\
138*7c478bd9Sstevel@tonic-gate 	uint8_t Xc;							\
139*7c478bd9Sstevel@tonic-gate 	for (Xcp = (const uint8_t *)(str); (Xc = *Xcp) != 0; Xcp++)	\
140*7c478bd9Sstevel@tonic-gate 		Xcrc = (Xcrc >> 8) ^ (table)[(Xcrc ^ Xc) & 0xFF];	\
141*7c478bd9Sstevel@tonic-gate 	(crc) = Xcrc;							\
142*7c478bd9Sstevel@tonic-gate 	(len) = Xcp - (const uint8_t *)(str);				\
143*7c478bd9Sstevel@tonic-gate }
145*7c478bd9Sstevel@tonic-gate /*
146*7c478bd9Sstevel@tonic-gate  * The polynomial we generally use in Solaris.
147*7c478bd9Sstevel@tonic-gate  */
148*7c478bd9Sstevel@tonic-gate #define	CRC32_POLY	0xEDB88320U
150*7c478bd9Sstevel@tonic-gate /*
151*7c478bd9Sstevel@tonic-gate  * The pre-computed table values for CRC32_POLY.
152*7c478bd9Sstevel@tonic-gate  */
153*7c478bd9Sstevel@tonic-gate #define	CRC32_TABLE						\
154*7c478bd9Sstevel@tonic-gate 	0x00000000U, 0x77073096U, 0xEE0E612CU, 0x990951BAU,	\
155*7c478bd9Sstevel@tonic-gate 	0x076DC419U, 0x706AF48FU, 0xE963A535U, 0x9E6495A3U,	\
156*7c478bd9Sstevel@tonic-gate 	0x0EDB8832U, 0x79DCB8A4U, 0xE0D5E91EU, 0x97D2D988U,	\
157*7c478bd9Sstevel@tonic-gate 	0x09B64C2BU, 0x7EB17CBDU, 0xE7B82D07U, 0x90BF1D91U,	\
158*7c478bd9Sstevel@tonic-gate 	0x1DB71064U, 0x6AB020F2U, 0xF3B97148U, 0x84BE41DEU,	\
159*7c478bd9Sstevel@tonic-gate 	0x1ADAD47DU, 0x6DDDE4EBU, 0xF4D4B551U, 0x83D385C7U,	\
160*7c478bd9Sstevel@tonic-gate 	0x136C9856U, 0x646BA8C0U, 0xFD62F97AU, 0x8A65C9ECU,	\
161*7c478bd9Sstevel@tonic-gate 	0x14015C4FU, 0x63066CD9U, 0xFA0F3D63U, 0x8D080DF5U,	\
162*7c478bd9Sstevel@tonic-gate 	0x3B6E20C8U, 0x4C69105EU, 0xD56041E4U, 0xA2677172U,	\
163*7c478bd9Sstevel@tonic-gate 	0x3C03E4D1U, 0x4B04D447U, 0xD20D85FDU, 0xA50AB56BU,	\
164*7c478bd9Sstevel@tonic-gate 	0x35B5A8FAU, 0x42B2986CU, 0xDBBBC9D6U, 0xACBCF940U,	\
165*7c478bd9Sstevel@tonic-gate 	0x32D86CE3U, 0x45DF5C75U, 0xDCD60DCFU, 0xABD13D59U,	\
166*7c478bd9Sstevel@tonic-gate 	0x26D930ACU, 0x51DE003AU, 0xC8D75180U, 0xBFD06116U,	\
167*7c478bd9Sstevel@tonic-gate 	0x21B4F4B5U, 0x56B3C423U, 0xCFBA9599U, 0xB8BDA50FU,	\
168*7c478bd9Sstevel@tonic-gate 	0x2802B89EU, 0x5F058808U, 0xC60CD9B2U, 0xB10BE924U,	\
169*7c478bd9Sstevel@tonic-gate 	0x2F6F7C87U, 0x58684C11U, 0xC1611DABU, 0xB6662D3DU,	\
170*7c478bd9Sstevel@tonic-gate 	0x76DC4190U, 0x01DB7106U, 0x98D220BCU, 0xEFD5102AU,	\
171*7c478bd9Sstevel@tonic-gate 	0x71B18589U, 0x06B6B51FU, 0x9FBFE4A5U, 0xE8B8D433U,	\
172*7c478bd9Sstevel@tonic-gate 	0x7807C9A2U, 0x0F00F934U, 0x9609A88EU, 0xE10E9818U,	\
173*7c478bd9Sstevel@tonic-gate 	0x7F6A0DBBU, 0x086D3D2DU, 0x91646C97U, 0xE6635C01U,	\
174*7c478bd9Sstevel@tonic-gate 	0x6B6B51F4U, 0x1C6C6162U, 0x856530D8U, 0xF262004EU,	\
175*7c478bd9Sstevel@tonic-gate 	0x6C0695EDU, 0x1B01A57BU, 0x8208F4C1U, 0xF50FC457U,	\
176*7c478bd9Sstevel@tonic-gate 	0x65B0D9C6U, 0x12B7E950U, 0x8BBEB8EAU, 0xFCB9887CU,	\
177*7c478bd9Sstevel@tonic-gate 	0x62DD1DDFU, 0x15DA2D49U, 0x8CD37CF3U, 0xFBD44C65U,	\
178*7c478bd9Sstevel@tonic-gate 	0x4DB26158U, 0x3AB551CEU, 0xA3BC0074U, 0xD4BB30E2U,	\
179*7c478bd9Sstevel@tonic-gate 	0x4ADFA541U, 0x3DD895D7U, 0xA4D1C46DU, 0xD3D6F4FBU,	\
180*7c478bd9Sstevel@tonic-gate 	0x4369E96AU, 0x346ED9FCU, 0xAD678846U, 0xDA60B8D0U,	\
181*7c478bd9Sstevel@tonic-gate 	0x44042D73U, 0x33031DE5U, 0xAA0A4C5FU, 0xDD0D7CC9U,	\
182*7c478bd9Sstevel@tonic-gate 	0x5005713CU, 0x270241AAU, 0xBE0B1010U, 0xC90C2086U,	\
183*7c478bd9Sstevel@tonic-gate 	0x5768B525U, 0x206F85B3U, 0xB966D409U, 0xCE61E49FU,	\
184*7c478bd9Sstevel@tonic-gate 	0x5EDEF90EU, 0x29D9C998U, 0xB0D09822U, 0xC7D7A8B4U,	\
185*7c478bd9Sstevel@tonic-gate 	0x59B33D17U, 0x2EB40D81U, 0xB7BD5C3BU, 0xC0BA6CADU,	\
186*7c478bd9Sstevel@tonic-gate 	0xEDB88320U, 0x9ABFB3B6U, 0x03B6E20CU, 0x74B1D29AU,	\
187*7c478bd9Sstevel@tonic-gate 	0xEAD54739U, 0x9DD277AFU, 0x04DB2615U, 0x73DC1683U,	\
188*7c478bd9Sstevel@tonic-gate 	0xE3630B12U, 0x94643B84U, 0x0D6D6A3EU, 0x7A6A5AA8U,	\
189*7c478bd9Sstevel@tonic-gate 	0xE40ECF0BU, 0x9309FF9DU, 0x0A00AE27U, 0x7D079EB1U,	\
190*7c478bd9Sstevel@tonic-gate 	0xF00F9344U, 0x8708A3D2U, 0x1E01F268U, 0x6906C2FEU,	\
191*7c478bd9Sstevel@tonic-gate 	0xF762575DU, 0x806567CBU, 0x196C3671U, 0x6E6B06E7U,	\
192*7c478bd9Sstevel@tonic-gate 	0xFED41B76U, 0x89D32BE0U, 0x10DA7A5AU, 0x67DD4ACCU,	\
193*7c478bd9Sstevel@tonic-gate 	0xF9B9DF6FU, 0x8EBEEFF9U, 0x17B7BE43U, 0x60B08ED5U,	\
194*7c478bd9Sstevel@tonic-gate 	0xD6D6A3E8U, 0xA1D1937EU, 0x38D8C2C4U, 0x4FDFF252U,	\
195*7c478bd9Sstevel@tonic-gate 	0xD1BB67F1U, 0xA6BC5767U, 0x3FB506DDU, 0x48B2364BU,	\
196*7c478bd9Sstevel@tonic-gate 	0xD80D2BDAU, 0xAF0A1B4CU, 0x36034AF6U, 0x41047A60U,	\
197*7c478bd9Sstevel@tonic-gate 	0xDF60EFC3U, 0xA867DF55U, 0x316E8EEFU, 0x4669BE79U,	\
198*7c478bd9Sstevel@tonic-gate 	0xCB61B38CU, 0xBC66831AU, 0x256FD2A0U, 0x5268E236U,	\
199*7c478bd9Sstevel@tonic-gate 	0xCC0C7795U, 0xBB0B4703U, 0x220216B9U, 0x5505262FU,	\
200*7c478bd9Sstevel@tonic-gate 	0xC5BA3BBEU, 0xB2BD0B28U, 0x2BB45A92U, 0x5CB36A04U,	\
201*7c478bd9Sstevel@tonic-gate 	0xC2D7FFA7U, 0xB5D0CF31U, 0x2CD99E8BU, 0x5BDEAE1DU,	\
202*7c478bd9Sstevel@tonic-gate 	0x9B64C2B0U, 0xEC63F226U, 0x756AA39CU, 0x026D930AU,	\
203*7c478bd9Sstevel@tonic-gate 	0x9C0906A9U, 0xEB0E363FU, 0x72076785U, 0x05005713U,	\
204*7c478bd9Sstevel@tonic-gate 	0x95BF4A82U, 0xE2B87A14U, 0x7BB12BAEU, 0x0CB61B38U,	\
205*7c478bd9Sstevel@tonic-gate 	0x92D28E9BU, 0xE5D5BE0DU, 0x7CDCEFB7U, 0x0BDBDF21U,	\
206*7c478bd9Sstevel@tonic-gate 	0x86D3D2D4U, 0xF1D4E242U, 0x68DDB3F8U, 0x1FDA836EU,	\
207*7c478bd9Sstevel@tonic-gate 	0x81BE16CDU, 0xF6B9265BU, 0x6FB077E1U, 0x18B74777U,	\
208*7c478bd9Sstevel@tonic-gate 	0x88085AE6U, 0xFF0F6A70U, 0x66063BCAU, 0x11010B5CU,	\
209*7c478bd9Sstevel@tonic-gate 	0x8F659EFFU, 0xF862AE69U, 0x616BFFD3U, 0x166CCF45U,	\
210*7c478bd9Sstevel@tonic-gate 	0xA00AE278U, 0xD70DD2EEU, 0x4E048354U, 0x3903B3C2U,	\
211*7c478bd9Sstevel@tonic-gate 	0xA7672661U, 0xD06016F7U, 0x4969474DU, 0x3E6E77DBU,	\
212*7c478bd9Sstevel@tonic-gate 	0xAED16A4AU, 0xD9D65ADCU, 0x40DF0B66U, 0x37D83BF0U,	\
213*7c478bd9Sstevel@tonic-gate 	0xA9BCAE53U, 0xDEBB9EC5U, 0x47B2CF7FU, 0x30B5FFE9U,	\
214*7c478bd9Sstevel@tonic-gate 	0xBDBDF21CU, 0xCABAC28AU, 0x53B39330U, 0x24B4A3A6U,	\
215*7c478bd9Sstevel@tonic-gate 	0xBAD03605U, 0xCDD70693U, 0x54DE5729U, 0x23D967BFU,	\
216*7c478bd9Sstevel@tonic-gate 	0xB3667A2EU, 0xC4614AB8U, 0x5D681B02U, 0x2A6F2B94U,	\
217*7c478bd9Sstevel@tonic-gate 	0xB40BBE37U, 0xC30C8EA1U, 0x5A05DF1BU, 0x2D02EF8DU
219*7c478bd9Sstevel@tonic-gate #ifdef _KERNEL
221*7c478bd9Sstevel@tonic-gate /*
222*7c478bd9Sstevel@tonic-gate  * The kernel's pre-computed table for CRC32_POLY.
223*7c478bd9Sstevel@tonic-gate  */
224*7c478bd9Sstevel@tonic-gate extern const uint32_t crc32_table[256];
226*7c478bd9Sstevel@tonic-gate #endif	/* _KERNEL */
228*7c478bd9Sstevel@tonic-gate #ifdef __cplusplus
229*7c478bd9Sstevel@tonic-gate }
230*7c478bd9Sstevel@tonic-gate #endif
232*7c478bd9Sstevel@tonic-gate #endif /* _SYS_CRC32_H */