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/*
* Copyright (c) 2003 VIA Networking, Inc. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*
* File: tether.c
*
* Purpose:
*
* Author: Tevin Chen
*
* Date: May 21, 1996
*
* Functions:
* ETHbyGetHashIndexByCrc32 - Calculate multicast hash value by CRC32
* ETHbIsBufferCrc32Ok - Check CRC value of the buffer if Ok or not
*
* Revision History:
*
*/
#include "device.h"
#include "tmacro.h"
#include "tcrc.h"
#include "tether.h"
/*--------------------- Static Definitions -------------------------*/
/*--------------------- Static Classes ----------------------------*/
/*--------------------- Static Variables --------------------------*/
/*--------------------- Static Functions --------------------------*/
/*--------------------- Export Variables --------------------------*/
/*
* Description: Calculate multicast hash value by CRC32
*
* Parameters:
* In:
* pbyMultiAddr - Multicast Address
* Out:
* none
*
* Return Value: Hash value
*
*/
unsigned char ETHbyGetHashIndexByCrc32 (unsigned char *pbyMultiAddr)
{
int ii;
unsigned char byTmpHash;
unsigned char byHash = 0;
// get the least 6-bits from CRC generator
byTmpHash = (unsigned char)(CRCdwCrc32(pbyMultiAddr, ETH_ALEN,
0xFFFFFFFFL) & 0x3F);
// reverse most bit to least bit
for (ii = 0; ii < (sizeof(byTmpHash) * 8); ii++) {
byHash <<= 1;
if (byTmpHash & 0x01)
byHash |= 1;
byTmpHash >>= 1;
}
// adjust 6-bits to the right most
return (byHash >> 2);
}
/*
* Description: Check CRC value of the buffer if Ok or not
*
* Parameters:
* In:
* pbyBuffer - pointer of buffer (normally is rx buffer)
* cbFrameLength - length of buffer, including CRC portion
* Out:
* none
*
* Return Value: true if ok; false if error.
*
*/
bool ETHbIsBufferCrc32Ok (unsigned char *pbyBuffer, unsigned int cbFrameLength)
{
unsigned long dwCRC;
dwCRC = CRCdwGetCrc32(pbyBuffer, cbFrameLength - 4);
if (cpu_to_le32(*((unsigned long *)(pbyBuffer + cbFrameLength - 4))) != dwCRC) {
return false;
}
return true;
}
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