WebSVN – HelenOS – Diff – /branches/network/uspace/srv/net/checksum.c


/*
 * Copyright (c) 2009 Lukas Mejdrech
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
/** @addtogroup net
 *  @{
 */
 
/** @file
 *  General CRC and checksum computation implementation.
 */
 
#include <sys/types.h>
 
#include "include/checksum.h"
 
/** Big-endian encoding CRC divider.
 */
#define CRC_DIVIDER_BE  0x04C11DB7
 
/** Little-endian encoding CRC divider.
 */
#define CRC_DIVIDER_LE  0xEDB88320
 
/** IP checksum value for computed zero checksum.
 *  Zero is returned as 0xFFFF (not flipped)
 */
#define IP_CHECKSUM_ZERO            0xFFFFu
 
uint32_t compute_crc32_le( uint32_t seed, uint8_t * data, size_t length ){
    size_t  index;
 
    while( length >= 8 ){
        seed ^= ( * data );
        for( index = 0; index < 8; ++ index ){
            if( seed & 1 ){
                seed = ( seed >> 1 ) ^ (( uint32_t ) CRC_DIVIDER_LE );
            }else{
                seed >>= 1;
            }
        }
        ++ data;
        length -= 8;
    }
    if( length > 0 ){
        seed ^= ( * data ) >> ( 8 - length );
        for( index = 0; index < length; ++ index ){
            if( seed & 1 ){
                seed = ( seed >> 1 ) ^ (( uint32_t ) CRC_DIVIDER_LE );
            }else{
                seed >>= 1;
            }
        }
        length -= 8;
    }
    return seed;
}
 
uint32_t compute_crc32_be( uint32_t seed, uint8_t * data, size_t length ){
    size_t  index;
 
    while( length >= 8 ){
        seed ^= ( * data ) << 24;
        for( index = 0; index < 8; ++ index ){
            if( seed & 0x80000000 ){
                seed = ( seed << 1 ) ^ (( uint32_t ) CRC_DIVIDER_BE );
            }else{
                seed <<= 1;
            }
        }
        ++ data;
        length -= 8;
    }
    if( length > 0 ){
        seed ^= (( * data ) & ( 0xFF << ( 8 - length ))) << 24;
        for( index = 0; index < length; ++ index ){
            if( seed & 0x80000000 ){
                seed = ( seed << 1 ) ^ (( uint32_t ) CRC_DIVIDER_BE );
            }else{
                seed <<= 1;
            }
        }
        length -= 8;
    }
    return seed;
}
 
uint32_t compute_checksum( uint32_t seed, uint8_t * data, size_t length ){
    size_t  index;
 
    // sum all the 16 bit fields
    for( index = 0; index + 1 < length; index += 2 ){
        seed += ( data[ index ] << 8 ) + data[ index + 1 ];
    }
 
    // last odd byte with zero padding
    if( index + 1 == length ){
        seed += data[ index ] << 8;
    }
 
    return seed;
}
 
uint16_t compact_checksum( uint32_t sum ){
    // shorten to the 16 bits
    while( sum >> 16 ) sum = ( sum & 0xFFFF ) + ( sum >> 16 );
 
    return ( uint16_t ) sum;
}
 
uint16_t flip_checksum( uint16_t checksum ){
    // flip, zero is returned as 0xFFFF (not flipped)
    return ( ~ checksum ) ? ( uint16_t ) ( ~ checksum ) : IP_CHECKSUM_ZERO;
}
 
uint16_t ip_checksum( uint8_t * data, size_t length ){
    return flip_checksum( compact_checksum( compute_checksum( 0, data, length )));
}
 
/** @}
 */
 

Rev 4743	Rev 4756
1	/*	1	/*
2	* Copyright (c) 2009 Lukas Mejdrech	2	* Copyright (c) 2009 Lukas Mejdrech
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	/** @addtogroup net	29	/** @addtogroup net
30	* @{	30	* @{
31	*/	31	*/
32		32
33	/** @file	33	/** @file
34	* General CRC and checksum computation implementation.	34	* General CRC and checksum computation implementation.
35	*/	35	*/
36		36
37	#include <sys/types.h>	37	#include <sys/types.h>
38		38
39	#include "include/checksum.h"	39	#include "include/checksum.h"
40		40
-		41	/** Big-endian encoding CRC divider.
-		42	*/
41	#define CRC_DIVIDER_BE 0x04C11DB7	43	#define CRC_DIVIDER_BE 0x04C11DB7
42		44
-		45	/** Little-endian encoding CRC divider.
-		46	*/
43	#define CRC_DIVIDER_LE 0xEDB88320	47	#define CRC_DIVIDER_LE 0xEDB88320
44		48
45	/** IP checksum value for computed zero checksum.	49	/** IP checksum value for computed zero checksum.
46	* Zero is returned as 0xFFFF (not flipped)	50	* Zero is returned as 0xFFFF (not flipped)
47	*/	51	*/
48	#define IP_CHECKSUM_ZERO 0xFFFFu	52	#define IP_CHECKSUM_ZERO 0xFFFFu
49		53
50	uint32_t compute_crc32_le( uint32_t seed, uint8_t * data, size_t length ){	54	uint32_t compute_crc32_le( uint32_t seed, uint8_t * data, size_t length ){
51	size_t index;	55	size_t index;
52		56
53	while( length >= 8 ){	57	while( length >= 8 ){
54	seed ^= ( * data );	58	seed ^= ( * data );
55	for( index = 0; index < 8; ++ index ){	59	for( index = 0; index < 8; ++ index ){
56	if( seed & 1 ){	60	if( seed & 1 ){
57	seed = ( seed >> 1 ) ^ (( uint32_t ) CRC_DIVIDER_LE );	61	seed = ( seed >> 1 ) ^ (( uint32_t ) CRC_DIVIDER_LE );
58	}else{	62	}else{
59	seed >>= 1;	63	seed >>= 1;
60	}	64	}
61	}	65	}
62	++ data;	66	++ data;
63	length -= 8;	67	length -= 8;
64	}	68	}
65	if( length > 0 ){	69	if( length > 0 ){
66	seed ^= ( * data ) >> ( 8 - length );	70	seed ^= ( * data ) >> ( 8 - length );
67	for( index = 0; index < length; ++ index ){	71	for( index = 0; index < length; ++ index ){
68	if( seed & 1 ){	72	if( seed & 1 ){
69	seed = ( seed >> 1 ) ^ (( uint32_t ) CRC_DIVIDER_LE );	73	seed = ( seed >> 1 ) ^ (( uint32_t ) CRC_DIVIDER_LE );
70	}else{	74	}else{
71	seed >>= 1;	75	seed >>= 1;
72	}	76	}
73	}	77	}
74	length -= 8;	78	length -= 8;
75	}	79	}
76	return seed;	80	return seed;
77	}	81	}
78		82
79	uint32_t compute_crc32_be( uint32_t seed, uint8_t * data, size_t length ){	83	uint32_t compute_crc32_be( uint32_t seed, uint8_t * data, size_t length ){
80	size_t index;	84	size_t index;
81		85
82	while( length >= 8 ){	86	while( length >= 8 ){
83	seed ^= ( * data ) << 24;	87	seed ^= ( * data ) << 24;
84	for( index = 0; index < 8; ++ index ){	88	for( index = 0; index < 8; ++ index ){
85	if( seed & 0x80000000 ){	89	if( seed & 0x80000000 ){
86	seed = ( seed << 1 ) ^ (( uint32_t ) CRC_DIVIDER_BE );	90	seed = ( seed << 1 ) ^ (( uint32_t ) CRC_DIVIDER_BE );
87	}else{	91	}else{
88	seed <<= 1;	92	seed <<= 1;
89	}	93	}
90	}	94	}
91	++ data;	95	++ data;
92	length -= 8;	96	length -= 8;
93	}	97	}
94	if( length > 0 ){	98	if( length > 0 ){
95	seed ^= (( * data ) & ( 0xFF << ( 8 - length ))) << 24;	99	seed ^= (( * data ) & ( 0xFF << ( 8 - length ))) << 24;
96	for( index = 0; index < length; ++ index ){	100	for( index = 0; index < length; ++ index ){
97	if( seed & 0x80000000 ){	101	if( seed & 0x80000000 ){
98	seed = ( seed << 1 ) ^ (( uint32_t ) CRC_DIVIDER_BE );	102	seed = ( seed << 1 ) ^ (( uint32_t ) CRC_DIVIDER_BE );
99	}else{	103	}else{
100	seed <<= 1;	104	seed <<= 1;
101	}	105	}
102	}	106	}
103	length -= 8;	107	length -= 8;
104	}	108	}
105	return seed;	109	return seed;
106	}	110	}
107		111
108	uint32_t compute_checksum( uint32_t seed, uint8_t * data, size_t length ){	112	uint32_t compute_checksum( uint32_t seed, uint8_t * data, size_t length ){
109	size_t index;	113	size_t index;
110		114
111	// sum all the 16 bit fields	115	// sum all the 16 bit fields
112	for( index = 0; index + 1 < length; index += 2 ){	116	for( index = 0; index + 1 < length; index += 2 ){
113	seed += ( data[ index ] << 8 ) + data[ index + 1 ];	117	seed += ( data[ index ] << 8 ) + data[ index + 1 ];
114	}	118	}
115		119
116	// last odd byte with zero padding	120	// last odd byte with zero padding
117	if( index + 1 == length ){	121	if( index + 1 == length ){
118	seed += data[ index ] << 8;	122	seed += data[ index ] << 8;
119	}	123	}
120		124
121	return seed;	125	return seed;
122	}	126	}
123		127
124	uint16_t compact_checksum( uint32_t sum ){	128	uint16_t compact_checksum( uint32_t sum ){
125	// shorten to the 16 bits	129	// shorten to the 16 bits
126	while( sum >> 16 ) sum = ( sum & 0xFFFF ) + ( sum >> 16 );	130	while( sum >> 16 ) sum = ( sum & 0xFFFF ) + ( sum >> 16 );
127		131
128	return ( uint16_t ) sum;	132	return ( uint16_t ) sum;
129	}	133	}
130		134
131	uint16_t flip_checksum( uint16_t checksum ){	135	uint16_t flip_checksum( uint16_t checksum ){
132	// flip, zero is returned as 0xFFFF (not flipped)	136	// flip, zero is returned as 0xFFFF (not flipped)
133	return ( ~ checksum ) ? ( uint16_t ) ( ~ checksum ) : IP_CHECKSUM_ZERO;	137	return ( ~ checksum ) ? ( uint16_t ) ( ~ checksum ) : IP_CHECKSUM_ZERO;
134	}	138	}
135		139
136	uint16_t ip_checksum( uint8_t * data, size_t length ){	140	uint16_t ip_checksum( uint8_t * data, size_t length ){
137	return flip_checksum( compact_checksum( compute_checksum( 0, data, length )));	141	return flip_checksum( compact_checksum( compute_checksum( 0, data, length )));
138	}	142	}
139		143
140	/** @}	144	/** @}
141	*/	145	*/
142		146

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(root)/branches/network/uspace/srv/net/checksum.c – Rev 4743 → 4756