/*====================================================================*
*
* fcs.c - ethernet frame check sequence functions
*
* see http://www.csm.ornl.gov/~dunigan/crc.html for an explanation
* of the CRC-32 algorithm reportedly used by PKZip, Ethernet, FDDI
* and other popular protocols for error detection;
*
* Motley Tools by Charles Maier <cmaier@cmassoc.net>;
* Copyright (c) 2001-2006 by Charles Maier Associates;
* Licensed under the Internet Software Consortium License;
*
*--------------------------------------------------------------------*/
#ifndef FCS_SOURCE
#define FCS_SOURCE
/*====================================================================*
* system header files;
*--------------------------------------------------------------------*/
#include <stdint.h>
/*====================================================================*
* variables;
*--------------------------------------------------------------------*/
static uint32_t CRCTable [256] =
{
0x00000000,
0x77073096,
0xee0e612c,
0x990951ba,
0x076dc419,
0x706af48f,
0xe963a535,
0x9e6495a3,
0x0edb8832,
0x79dcb8a4,
0xe0d5e91e,
0x97d2d988,
0x09b64c2b,
0x7eb17cbd,
0xe7b82d07,
0x90bf1d91,
0x1db71064,
0x6ab020f2,
0xf3b97148,
0x84be41de,
0x1adad47d,
0x6ddde4eb,
0xf4d4b551,
0x83d385c7,
0x136c9856,
0x646ba8c0,
0xfd62f97a,
0x8a65c9ec,
0x14015c4f,
0x63066cd9,
0xfa0f3d63,
0x8d080df5,
0x3b6e20c8,
0x4c69105e,
0xd56041e4,
0xa2677172,
0x3c03e4d1,
0x4b04d447,
0xd20d85fd,
0xa50ab56b,
0x35b5a8fa,
0x42b2986c,
0xdbbbc9d6,
0xacbcf940,
0x32d86ce3,
0x45df5c75,
0xdcd60dcf,
0xabd13d59,
0x26d930ac,
0x51de003a,
0xc8d75180,
0xbfd06116,
0x21b4f4b5,
0x56b3c423,
0xcfba9599,
0xb8bda50f,
0x2802b89e,
0x5f058808,
0xc60cd9b2,
0xb10be924,
0x2f6f7c87,
0x58684c11,
0xc1611dab,
0xb6662d3d,
0x76dc4190,
0x01db7106,
0x98d220bc,
0xefd5102a,
0x71b18589,
0x06b6b51f,
0x9fbfe4a5,
0xe8b8d433,
0x7807c9a2,
0x0f00f934,
0x9609a88e,
0xe10e9818,
0x7f6a0dbb,
0x086d3d2d,
0x91646c97,
0xe6635c01,
0x6b6b51f4,
0x1c6c6162,
0x856530d8,
0xf262004e,
0x6c0695ed,
0x1b01a57b,
0x8208f4c1,
0xf50fc457,
0x65b0d9c6,
0x12b7e950,
0x8bbeb8ea,
0xfcb9887c,
0x62dd1ddf,
0x15da2d49,
0x8cd37cf3,
0xfbd44c65,
0x4db26158,
0x3ab551ce,
0xa3bc0074,
0xd4bb30e2,
0x4adfa541,
0x3dd895d7,
0xa4d1c46d,
0xd3d6f4fb,
0x4369e96a,
0x346ed9fc,
0xad678846,
0xda60b8d0,
0x44042d73,
0x33031de5,
0xaa0a4c5f,
0xdd0d7cc9,
0x5005713c,
0x270241aa,
0xbe0b1010,
0xc90c2086,
0x5768b525,
0x206f85b3,
0xb966d409,
0xce61e49f,
0x5edef90e,
0x29d9c998,
0xb0d09822,
0xc7d7a8b4,
0x59b33d17,
0x2eb40d81,
0xb7bd5c3b,
0xc0ba6cad,
0xedb88320,
0x9abfb3b6,
0x03b6e20c,
0x74b1d29a,
0xead54739,
0x9dd277af,
0x04db2615,
0x73dc1683,
0xe3630b12,
0x94643b84,
0x0d6d6a3e,
0x7a6a5aa8,
0xe40ecf0b,
0x9309ff9d,
0x0a00ae27,
0x7d079eb1,
0xf00f9344,
0x8708a3d2,
0x1e01f268,
0x6906c2fe,
0xf762575d,
0x806567cb,
0x196c3671,
0x6e6b06e7,
0xfed41b76,
0x89d32be0,
0x10da7a5a,
0x67dd4acc,
0xf9b9df6f,
0x8ebeeff9,
0x17b7be43,
0x60b08ed5,
0xd6d6a3e8,
0xa1d1937e,
0x38d8c2c4,
0x4fdff252,
0xd1bb67f1,
0xa6bc5767,
0x3fb506dd,
0x48b2364b,
0xd80d2bda,
0xaf0a1b4c,
0x36034af6,
0x41047a60,
0xdf60efc3,
0xa867df55,
0x316e8eef,
0x4669be79,
0xcb61b38c,
0xbc66831a,
0x256fd2a0,
0x5268e236,
0xcc0c7795,
0xbb0b4703,
0x220216b9,
0x5505262f,
0xc5ba3bbe,
0xb2bd0b28,
0x2bb45a92,
0x5cb36a04,
0xc2d7ffa7,
0xb5d0cf31,
0x2cd99e8b,
0x5bdeae1d,
0x9b64c2b0,
0xec63f226,
0x756aa39c,
0x026d930a,
0x9c0906a9,
0xeb0e363f,
0x72076785,
0x05005713,
0x95bf4a82,
0xe2b87a14,
0x7bb12bae,
0x0cb61b38,
0x92d28e9b,
0xe5d5be0d,
0x7cdcefb7,
0x0bdbdf21,
0x86d3d2d4,
0xf1d4e242,
0x68ddb3f8,
0x1fda836e,
0x81be16cd,
0xf6b9265b,
0x6fb077e1,
0x18b74777,
0x88085ae6,
0xff0f6a70,
0x66063bca,
0x11010b5c,
0x8f659eff,
0xf862ae69,
0x616bffd3,
0x166ccf45,
0xa00ae278,
0xd70dd2ee,
0x4e048354,
0x3903b3c2,
0xa7672661,
0xd06016f7,
0x4969474d,
0x3e6e77db,
0xaed16a4a,
0xd9d65adc,
0x40df0b66,
0x37d83bf0,
0xa9bcae53,
0xdebb9ec5,
0x47b2cf7f,
0x30b5ffe9,
0xbdbdf21c,
0xcabac28a,
0x53b39330,
0x24b4a3a6,
0xbad03605,
0xcdd70693,
0x54de5729,
0x23d967bf,
0xb3667a2e,
0xc4614ab8,
0x5d681b02,
0x2a6f2b94,
0xb40bbe37,
0xc30c8ea1,
0x5a05df1b,
0x2d02ef8d
};
/*====================================================================*
*
* uint32_t ReflectBits (uint32_t value, uint32_t bits);
*
* return the bitwise mirror image of an integer value;
*
* Motley Tools by Charles Maier <cmaier@cmassoc.net>;
* Copyright (c) 2001-2006 by Charles Maier Associates;
* Licensed under the Internet Software Consortium License;
*
*--------------------------------------------------------------------*/
#if 0
static uint32_t ReflectBits (uint32_t value, uint32_t bits)
{
uint32_t image = 0;
uint32_t bit;
for (bit = 0; bit < bits; bit++)
{
if (value & 1)
{
image |= 1 << (bits - bit - 1);
}
value >>= 1;
}
return (image);
}
#endif
/*====================================================================*
*
* void InitCRCTable (void);
*
* write frame control sequence table with values; this function is
* only needed to populate an empty CRCTable;
*
* Motley Tools by Charles Maier <cmaier@cmassoc.net>;
* Copyright (c) 2001-2006 by Charles Maier Associates;
* Licensed under the Internet Software Consortium License;
*
*--------------------------------------------------------------------*/
#if 0
static void InitCRCTable (uint32_t CRCTable [])
{
extern uint32_t CRCTable [];
uint32_t word;
uint32_t bit;
for (word = 0; word < 256; word++)
{
uint32_t crc = ReflectBits (word, 8) << 24;
for (bit = 0; bit < 8; bit++)
{
crc = (crc << 1) ^ ((crc & 0x80000000)? 0x04c11db7: 0);
}
CRCTable [word] = ReflectBits (crc, 32);
}
return;
}
#endif
/*====================================================================*
*
* uint32_t ComputeCRC (uint8_t buffer [], uint32_t length);
*
*
*
* Motley Tools by Charles Maier <cmaier@cmassoc.net>;
* Copyright (c) 2001-2006 by Charles Maier Associates;
* Licensed under the Internet Software Consortium License;
*
*--------------------------------------------------------------------*/
uint32_t ComputeCRC (uint8_t buffer [], uint32_t length)
{
extern uint32_t CRCTable [];
uint32_t crc = ~0;
while (length--)
{
crc = (crc >> 8) ^ CRCTable [(crc & 0xff) ^ *buffer++];
}
return (~crc);
}
/*====================================================================*
*
* int VerifyCRC (uint8_t buffer [], uint32_t length, uint32_t crc);
*
*
*
* Motley Tools by Charles Maier <cmaier@cmassoc.net>;
* Copyright (c) 2001-2006 by Charles Maier Associates;
* Licensed under the Internet Software Consortium License;
*
*--------------------------------------------------------------------*/
int VerifyCRC (uint8_t buffer [], uint32_t length, uint32_t crc)
{
return (crc = ComputeCRC (buffer, length));
}
/*====================================================================*
*
* int main (int argc, const char * argv [])
*
*
* Motley Tools by Charles Maier <cmaier@cmassoc.net>;
* Copyright (c) 2001-2006 by Charles Maier Associates;
* Licensed under the Internet Software Consortium License;
*
*--------------------------------------------------------------------*/
#if 0
#include <stdio.h>
static uint8_t frame [192]=
{
0x00,
0x00,
0x00,
0x00,
0x00,
0x01,
0x00,
0x00,
0x00,
0x00,
0x00,
0x02,
0x08,
0x00,
0x45,
0x60,
0x00,
0xAE,
0x00,
0x00,
0x40,
0x00,
0x40,
0x11,
0xDF,
0xB9,
0xAC,
0x11,
0x01,
0x02,
0xAC,
0x11,
0x01,
0x01,
0x00,
0x00,
0x00,
0x00,
0x00,
0x9A,
0xA4,
0x94,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00,
0x00
};
int main (int argc, const char * argv [])
{
uint32_t size = sizeof (frame);
uint32_t word;
uint8_t blah [] =
{
0x00,
0xB0,
0x52,
0x11,
0x22,
0x33,
0x00,
0x0A,
0x5E,
0x5A,
0x27,
0x38,
0x88,
0xE1,
0x00,
0x28,
0xA0,
0x00,
0xB0,
0x52,
0x02
};
while (size > 160)
{
word = ComputeCRC (frame, size);
printf ("%d %08X\n", size, word);
size -= sizeof (word);
}
size = 21;
word = ComputeCRC (blah, size);
printf ("%d %08X\n", size, word);
return (0);
}
#endif
/*====================================================================*
*
*--------------------------------------------------------------------*/
#endif