1 /*
2 * Copyright (c) 2003 VIA Networking, Inc. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License along
15 * with this program; if not, write to the Free Software Foundation, Inc.,
16 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 *
19 * File: tether.c
20 *
21 * Purpose:
22 *
23 * Author: Tevin Chen
24 *
25 * Date: May 21, 1996
26 *
27 * Functions:
28 * ETHbyGetHashIndexByCrc32 - Caculate multicast hash value by CRC32
29 * ETHbIsBufferCrc32Ok - Check CRC value of the buffer if Ok or not
30 *
31 * Revision History:
32 *
33 */
34
35 #include "device.h"
36 #include "tmacro.h"
37 #include "tcrc.h"
38 #include "tether.h"
39
40 /*--------------------- Static Definitions -------------------------*/
41
42 /*--------------------- Static Classes ----------------------------*/
43
44 /*--------------------- Static Variables --------------------------*/
45
46 /*--------------------- Static Functions --------------------------*/
47
48 /*--------------------- Export Variables --------------------------*/
49
50
51
52 /*
53 * Description: Caculate multicast hash value by CRC32
54 *
55 * Parameters:
56 * In:
57 * pbyMultiAddr - Multicast Address
58 * Out:
59 * none
60 *
61 * Return Value: Hash value
62 *
63 */
ETHbyGetHashIndexByCrc32(PBYTE pbyMultiAddr)64 BYTE ETHbyGetHashIndexByCrc32(PBYTE pbyMultiAddr)
65 {
66 int ii;
67 BYTE byTmpHash;
68 BYTE byHash = 0;
69
70 /* get the least 6-bits from CRC generator */
71 byTmpHash = (BYTE)(CRCdwCrc32(pbyMultiAddr, ETH_ALEN,
72 0xFFFFFFFFL) & 0x3F);
73 /* reverse most bit to least bit */
74 for (ii = 0; ii < (sizeof(byTmpHash) * 8); ii++) {
75 byHash <<= 1;
76 if (byTmpHash & 0x01)
77 byHash |= 1;
78 byTmpHash >>= 1;
79 }
80
81 /* adjust 6-bits to the right most */
82 return byHash >> 2;
83 }
84
85
86 /*
87 * Description: Check CRC value of the buffer if Ok or not
88 *
89 * Parameters:
90 * In:
91 * pbyBuffer - pointer of buffer (normally is rx buffer)
92 * cbFrameLength - length of buffer, including CRC portion
93 * Out:
94 * none
95 *
96 * Return Value: TRUE if ok; FALSE if error.
97 *
98 */
ETHbIsBufferCrc32Ok(PBYTE pbyBuffer,unsigned int cbFrameLength)99 BOOL ETHbIsBufferCrc32Ok(PBYTE pbyBuffer, unsigned int cbFrameLength)
100 {
101 DWORD dwCRC;
102
103 dwCRC = CRCdwGetCrc32(pbyBuffer, cbFrameLength - 4);
104 if (cpu_to_le32(*((PDWORD)(pbyBuffer + cbFrameLength - 4))) != dwCRC)
105 return FALSE;
106 return TRUE;
107 }
108
109