199 lines
4.0 KiB
C
199 lines
4.0 KiB
C
/* crc.c
|
|
* crc checksum generation and calculation functions: crc.c
|
|
*
|
|
* Copyright (c) 2007 by Intel Corporation.
|
|
*
|
|
* Author: Mike Harvey <michael.harvey@intel.com>
|
|
*
|
|
* Wireshark - Network traffic analyzer
|
|
* By Gerald Combs <gerald@wireshark.org>
|
|
* Copyright 1999 Gerald Combs
|
|
*
|
|
* SPDX-License-Identifier: GPL-2.0-or-later
|
|
*/
|
|
|
|
#include "crc.h"
|
|
|
|
#define WMAX_MAC_CRC32_POLYNOMIAL 0x04c11db7U /* polynomial used in calculating the CRC-32 checksum */
|
|
#define CCITT_X25_CRC16_POLYNOMIAL 0x1021 /* polynomial used in calculating the CRC-16 checksum */
|
|
#define WMAX_MAC_CRC8_POLYNOMIAL 0x07 /* polynomial used in calculating the CRC-8 checksum */
|
|
#define CRC32_INITIAL_VALUE 0xFFFFFFFF
|
|
#define CRC16_INITIAL_VALUE 0xFFFF
|
|
|
|
#ifndef STATIC_DATA
|
|
static guint8 crc8_table[256];
|
|
static guint32 crc32_table[256];
|
|
|
|
extern guint16 crc16_table[256];
|
|
|
|
/*
|
|
void wimax_mac_gen_crc32_table(void)
|
|
|
|
REQUIRES: The functions must be called only once to initialze CRC table
|
|
|
|
DESCRIPTION: Generate the table of CRC remainders
|
|
for all possible bytes
|
|
|
|
ARGS:
|
|
|
|
RETURNS:
|
|
|
|
SIDE EFFECTS:
|
|
|
|
*/
|
|
void wimax_mac_gen_crc32_table(void)
|
|
{
|
|
guint32 i, bit;
|
|
guint32 crc;
|
|
|
|
/* little-endian (reflected) algorithm */
|
|
for ( i = 0; i < G_N_ELEMENTS(crc32_table); i++ )
|
|
{
|
|
crc = ( i << 24 );
|
|
for ( bit = 0; bit < 8; bit++ )
|
|
{
|
|
if ( crc & 0x80000000U )
|
|
crc = ( crc << 1 ) ^ WMAX_MAC_CRC32_POLYNOMIAL;
|
|
else
|
|
crc = ( crc << 1 );
|
|
}
|
|
crc32_table[i] = crc;
|
|
}
|
|
}
|
|
|
|
/*
|
|
void wimax_mac_gen_crc8_table(void)
|
|
|
|
REQUIRES: The functions must be called only once to initialze CRC table
|
|
|
|
DESCRIPTION: Generate the table of CRC remainders
|
|
for all possible bytes
|
|
|
|
ARGS:
|
|
|
|
RETURNS:
|
|
|
|
SIDE EFFECTS:
|
|
|
|
*/
|
|
void wimax_mac_gen_crc8_table(void)
|
|
{
|
|
guint i, bit;
|
|
guint8 crc;
|
|
|
|
for ( i = 0; i < G_N_ELEMENTS(crc8_table); i++ )
|
|
{
|
|
crc = i;
|
|
for ( bit = 0; bit < 8; bit++ )
|
|
{
|
|
if ( crc & 0x80 )
|
|
crc = ( crc << 1 ) ^ WMAX_MAC_CRC8_POLYNOMIAL;
|
|
else
|
|
crc = ( crc << 1 );
|
|
}
|
|
crc8_table[i] = crc;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
|
|
guint32 wimax_mac_calc_crc32(guint8 *data, guint data_len)
|
|
|
|
REQUIRES: wimax_mac_gen_crc32_table() must be called before
|
|
|
|
DESCRIPTION: Calculate the 32-bit CRC from a given data block
|
|
|
|
ARGS: data - pointer to data
|
|
data_len - length of data (in bytes)
|
|
|
|
RETURNS: calculated crc32
|
|
|
|
SIDE EFFECTS:
|
|
|
|
*/
|
|
guint32 wimax_mac_calc_crc32(const guint8 *data, guint data_len)
|
|
{
|
|
guint32 crc=CRC32_INITIAL_VALUE;
|
|
guint i, j;
|
|
|
|
for ( j = 0; j < data_len; j++ )
|
|
{
|
|
i = ( (guint8)(crc>>24) ^ data[j] ) & 0xff;
|
|
crc = ( crc<<8 ) ^ crc32_table[i];
|
|
}
|
|
return ~crc;
|
|
}
|
|
|
|
/*
|
|
|
|
guint16 wimax_mac_calc_crc16(guint8 *data, guint data_len)
|
|
|
|
REQUIRES: crc16_table[] in crc_data.c
|
|
|
|
DESCRIPTION: Calculate the 16-bit CRC from a given data block
|
|
|
|
ARGS: data - pointer to data
|
|
data_len - length of data (in bytes)
|
|
|
|
RETURNS: calculated crc16
|
|
|
|
SIDE EFFECTS:
|
|
|
|
*/
|
|
guint16 wimax_mac_calc_crc16(const guint8 *data, guint data_len)
|
|
{
|
|
guint32 crc=CRC16_INITIAL_VALUE;
|
|
guint j;
|
|
|
|
for ( j = 0; j < data_len; j++ )
|
|
{
|
|
crc ^= data[j] << 8;
|
|
crc = (crc << 8) ^ crc16_table[(crc & 0xff00) >> 8];
|
|
}
|
|
crc ^= 0xFFFF; /* Invert the output. */
|
|
crc &= 0xFFFF;
|
|
return crc;
|
|
}
|
|
|
|
/*
|
|
|
|
guint8 wimax_mac_calc_crc8(guint8 *data, guint data_len)
|
|
|
|
REQUIRES: wimax_mac_gen_crc8_table() must be called before
|
|
|
|
DESCRIPTION: Calculate the 8-bit CRC from a given data block
|
|
|
|
ARGS: data - pointer to data
|
|
data_len - length of data (in bytes)
|
|
|
|
RETURNS: calculated crc8
|
|
|
|
SIDE EFFECTS:
|
|
|
|
*/
|
|
guint8 wimax_mac_calc_crc8(const guint8 *data, guint data_len)
|
|
{
|
|
guint8 crc=0;
|
|
guint i;
|
|
|
|
for(i = 0; i < data_len; i++)
|
|
{
|
|
crc = crc8_table[data[i]^crc];
|
|
}
|
|
return crc;
|
|
}
|
|
|
|
/*
|
|
* Editor modelines - http://www.wireshark.org/tools/modelines.html
|
|
*
|
|
* Local Variables:
|
|
* c-basic-offset: 2
|
|
* tab-width: 8
|
|
* indent-tabs-mode: nil
|
|
* End:
|
|
*
|
|
* ex: set shiftwidth=2 tabstop=8 expandtab:
|
|
* :indentSize=2:tabSize=8:noTabs=true:
|
|
*/
|