| /* |
| * 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 - Caculate 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: Caculate multicast hash value by CRC32 |
| * |
| * Parameters: |
| * In: |
| * pbyMultiAddr - Multicast Address |
| * Out: |
| * none |
| * |
| * Return Value: Hash value |
| * |
| */ |
| BYTE ETHbyGetHashIndexByCrc32 (PBYTE pbyMultiAddr) |
| { |
| int ii; |
| BYTE byTmpHash; |
| BYTE byHash = 0; |
| |
| // get the least 6-bits from CRC generator |
| byTmpHash = (BYTE)(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 (PBYTE pbyBuffer, UINT cbFrameLength) |
| { |
| DWORD dwCRC; |
| |
| dwCRC = CRCdwGetCrc32(pbyBuffer, cbFrameLength - 4); |
| if (cpu_to_le32(*((PDWORD)(pbyBuffer + cbFrameLength - 4))) != dwCRC) { |
| return FALSE; |
| } |
| return TRUE; |
| } |
| |