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| 4075 | mejdrech | 1 | /* |
| 2 | * Copyright (c) 2009 Lukas Mejdrech |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 29 | /** @addtogroup net |
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| 30 | * @{ |
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| 31 | */ |
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| 32 | |||
| 33 | /** @file |
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| 4505 | mejdrech | 34 | * General CRC and checksum computation. |
| 4075 | mejdrech | 35 | */ |
| 36 | |||
| 4743 | mejdrech | 37 | #ifndef __NET_CHECKSUM_H__ |
| 38 | #define __NET_CHECKSUM_H__ |
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| 4075 | mejdrech | 39 | |
| 40 | #include <byteorder.h> |
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| 41 | |||
| 42 | #include <sys/types.h> |
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| 43 | |||
| 44 | /** Computes CRC32 value. |
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| 45 | * @param seed Initial value. Often used as 0 or ~0. Input parameter. |
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| 46 | * @param data Pointer to the beginning of data to process. Input parameter. |
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| 47 | * @param length Length of the data in bits. Input parameter. |
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| 48 | * @returns The computed CRC32 of the length bits of the data. |
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| 49 | */ |
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| 50 | #ifdef ARCH_IS_BIG_ENDIAN |
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| 51 | #define compute_crc32( seed, data, length ) compute_crc32_be( seed, ( uint8_t * ) data, length ) |
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| 52 | #else |
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| 53 | #define compute_crc32( seed, data, length ) compute_crc32_le( seed, ( uint8_t * ) data, length ) |
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| 54 | #endif |
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| 55 | |||
| 56 | /** Computes CRC32 value in the little-endian environment. |
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| 57 | * @param seed Initial value. Often used as 0 or ~0. Input parameter. |
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| 58 | * @param data Pointer to the beginning of data to process. Input parameter. |
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| 59 | * @param length Length of the data in bits. Input parameter. |
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| 60 | * @returns The computed CRC32 of the length bits of the data. |
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| 61 | */ |
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| 4558 | mejdrech | 62 | uint32_t compute_crc32_le( uint32_t seed, uint8_t * data, size_t length ); |
| 4075 | mejdrech | 63 | |
| 64 | /** Computes CRC32 value in the big-endian environment. |
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| 65 | * @param seed Initial value. Often used as 0 or ~0. Input parameter. |
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| 66 | * @param data Pointer to the beginning of data to process. Input parameter. |
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| 67 | * @param length Length of the data in bits. Input parameter. |
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| 68 | * @returns The computed CRC32 of the length bits of the data. |
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| 69 | */ |
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| 4558 | mejdrech | 70 | uint32_t compute_crc32_be( uint32_t seed, uint8_t * data, size_t length ); |
| 4075 | mejdrech | 71 | |
| 4505 | mejdrech | 72 | /** Computes sum of the 2 byte fields. |
| 73 | * Padds one zero (0) byte if odd. |
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| 74 | * @param seed Initial value. Often used as 0 or ~0. Input parameter. |
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| 75 | * @param data Pointer to the beginning of data to process. Input parameter. |
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| 76 | * @param length Length of the data in bytes. Input parameter. |
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| 77 | * @returns The computed checksum of the length bytes of the data. |
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| 78 | */ |
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| 4558 | mejdrech | 79 | uint32_t compute_checksum( uint32_t seed, uint8_t * data, size_t length ); |
| 4505 | mejdrech | 80 | |
| 81 | /** Compacts the computed checksum to the 16 bit number adding the carries. |
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| 4699 | mejdrech | 82 | * @param sum Computed checksum. Input parameter. |
| 4505 | mejdrech | 83 | * @returns Compacted computed checksum to the 16 bits. |
| 84 | */ |
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| 85 | uint16_t compact_checksum( uint32_t sum ); |
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| 86 | |||
| 4722 | mejdrech | 87 | /** Returns or flips the checksum if zero. |
| 88 | * @param checksum The computed checksum. Input parameter. |
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| 89 | * @returns The internet protocol header checksum. |
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| 90 | * @returns 0xFFFF if the computed checksum is zero. |
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| 91 | */ |
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| 92 | uint16_t flip_checksum( uint16_t checksum ); |
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| 93 | |||
| 4711 | mejdrech | 94 | /** Computes the ip header checksum. |
| 95 | * To compute the checksum of a new packet, the checksum header field must be zero. |
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| 96 | * To check the checksum of a received packet, the checksum may be left set. |
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| 4722 | mejdrech | 97 | * The zero (0) value will be returned in this case if valid. |
| 4711 | mejdrech | 98 | * @param data The header data. Input parameter. |
| 99 | * @param length The header length in bytes. Input parameter. |
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| 100 | * @returns The internet protocol header checksum. |
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| 101 | * @returns 0xFFFF if the computed checksum is zero. |
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| 102 | */ |
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| 103 | uint16_t ip_checksum( uint8_t * data, size_t length ); |
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| 104 | |||
| 4075 | mejdrech | 105 | #endif |
| 106 | |||
| 107 | /** @} |
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| 108 | */ |