| 0,0 → 1,141 |
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| /* |
| * 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" |
| |
| #define CRC_DIVIDER_BE 0x04C11DB7 |
| |
| #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 ))); |
| } |
| |
| /** @} |
| */ |
| Property changes: |
|---|
| Added: svn:eol-style |
|---|
| +native |
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| \ No newline at end of property |
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