1/******************************************************************************
2 *
3 *  Copyright (C) 2012 Broadcom Corporation
4 *
5 *  Licensed under the Apache License, Version 2.0 (the "License");
6 *  you may not use this file except in compliance with the License.
7 *  You may obtain a copy of the License at:
8 *
9 *  http://www.apache.org/licenses/LICENSE-2.0
10 *
11 *  Unless required by applicable law or agreed to in writing, software
12 *  distributed under the License is distributed on an "AS IS" BASIS,
13 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 *  See the License for the specific language governing permissions and
15 *  limitations under the License.
16 *
17 ******************************************************************************/
18#include "OverrideLog.h"
19#include "CrcChecksum.h"
20#include <sys/types.h>
21#include <sys/stat.h>
22#include <fcntl.h>
23#include <errno.h>
24#include <string>
25#define LOG_TAG "NfcNciHal"
26
27
28static const unsigned short crctab [256] =
29{
30    0x0000, 0xc0c1, 0xc181, 0x0140, 0xc301, 0x03c0, 0x0280, 0xc241,
31    0xc601, 0x06c0, 0x0780, 0xc741, 0x0500, 0xc5c1, 0xc481, 0x0440,
32    0xcc01, 0x0cc0, 0x0d80, 0xcd41, 0x0f00, 0xcfc1, 0xce81, 0x0e40,
33    0x0a00, 0xcac1, 0xcb81, 0x0b40, 0xc901, 0x09c0, 0x0880, 0xc841,
34    0xd801, 0x18c0, 0x1980, 0xd941, 0x1b00, 0xdbc1, 0xda81, 0x1a40,
35    0x1e00, 0xdec1, 0xdf81, 0x1f40, 0xdd01, 0x1dc0, 0x1c80, 0xdc41,
36    0x1400, 0xd4c1, 0xd581, 0x1540, 0xd701, 0x17c0, 0x1680, 0xd641,
37    0xd201, 0x12c0, 0x1380, 0xd341, 0x1100, 0xd1c1, 0xd081, 0x1040,
38    0xf001, 0x30c0, 0x3180, 0xf141, 0x3300, 0xf3c1, 0xf281, 0x3240,
39    0x3600, 0xf6c1, 0xf781, 0x3740, 0xf501, 0x35c0, 0x3480, 0xf441,
40    0x3c00, 0xfcc1, 0xfd81, 0x3d40, 0xff01, 0x3fc0, 0x3e80, 0xfe41,
41    0xfa01, 0x3ac0, 0x3b80, 0xfb41, 0x3900, 0xf9c1, 0xf881, 0x3840,
42    0x2800, 0xe8c1, 0xe981, 0x2940, 0xeb01, 0x2bc0, 0x2a80, 0xea41,
43    0xee01, 0x2ec0, 0x2f80, 0xef41, 0x2d00, 0xedc1, 0xec81, 0x2c40,
44    0xe401, 0x24c0, 0x2580, 0xe541, 0x2700, 0xe7c1, 0xe681, 0x2640,
45    0x2200, 0xe2c1, 0xe381, 0x2340, 0xe101, 0x21c0, 0x2080, 0xe041,
46    0xa001, 0x60c0, 0x6180, 0xa141, 0x6300, 0xa3c1, 0xa281, 0x6240,
47    0x6600, 0xa6c1, 0xa781, 0x6740, 0xa501, 0x65c0, 0x6480, 0xa441,
48    0x6c00, 0xacc1, 0xad81, 0x6d40, 0xaf01, 0x6fc0, 0x6e80, 0xae41,
49    0xaa01, 0x6ac0, 0x6b80, 0xab41, 0x6900, 0xa9c1, 0xa881, 0x6840,
50    0x7800, 0xb8c1, 0xb981, 0x7940, 0xbb01, 0x7bc0, 0x7a80, 0xba41,
51    0xbe01, 0x7ec0, 0x7f80, 0xbf41, 0x7d00, 0xbdc1, 0xbc81, 0x7c40,
52    0xb401, 0x74c0, 0x7580, 0xb541, 0x7700, 0xb7c1, 0xb681, 0x7640,
53    0x7200, 0xb2c1, 0xb381, 0x7340, 0xb101, 0x71c0, 0x7080, 0xb041,
54    0x5000, 0x90c1, 0x9181, 0x5140, 0x9301, 0x53c0, 0x5280, 0x9241,
55    0x9601, 0x56c0, 0x5780, 0x9741, 0x5500, 0x95c1, 0x9481, 0x5440,
56    0x9c01, 0x5cc0, 0x5d80, 0x9d41, 0x5f00, 0x9fc1, 0x9e81, 0x5e40,
57    0x5a00, 0x9ac1, 0x9b81, 0x5b40, 0x9901, 0x59c0, 0x5880, 0x9841,
58    0x8801, 0x48c0, 0x4980, 0x8941, 0x4b00, 0x8bc1, 0x8a81, 0x4a40,
59    0x4e00, 0x8ec1, 0x8f81, 0x4f40, 0x8d01, 0x4dc0, 0x4c80, 0x8c41,
60    0x4400, 0x84c1, 0x8581, 0x4540, 0x8701, 0x47c0, 0x4680, 0x8641,
61    0x8201, 0x42c0, 0x4380, 0x8341, 0x4100, 0x81c1, 0x8081, 0x4040,
62};
63
64
65/*******************************************************************************
66**
67** Function         crcChecksumCompute
68**
69** Description      Compute a checksum on a buffer of data.
70**
71** Returns          2-byte checksum.
72**
73*******************************************************************************/
74unsigned short crcChecksumCompute (const unsigned char *buffer, int bufferLen)
75{
76    register unsigned short crc = 0;
77    const register unsigned char  *cp = buffer;
78    register          int   cnt = bufferLen;
79
80    while (cnt--)
81    {
82        crc = ((crc >> 8) & 0xff) ^ crctab[(crc & 0xff) ^ *cp++];
83    }
84    return(crc);
85}
86
87
88/*******************************************************************************
89**
90** Function         crcChecksumVerifyIntegrity
91**
92** Description      Detect any corruption in a file by computing a checksum.
93**                  filename: file name.
94**
95** Returns          True if file is good.
96**
97*******************************************************************************/
98BOOLEAN crcChecksumVerifyIntegrity (const char* filename)
99{
100    ALOGD ("%s: filename=%s", __FUNCTION__, filename);
101    BOOLEAN isGood = FALSE;
102    int fileStream = open (filename, O_RDONLY);
103    if (fileStream >= 0)
104    {
105        unsigned short checksum = 0;
106        std::string data;
107        size_t actualReadCrc = read (fileStream, &checksum, sizeof(checksum));
108        while (true)
109        {
110            char buffer [1024];
111            ssize_t actualReadData = read (fileStream, buffer, sizeof(buffer));
112            if (actualReadData > 0)
113                data.append (buffer, actualReadData);
114            else
115                break;
116        }
117        close (fileStream);
118        if ((actualReadCrc == sizeof(checksum)) && (data.size() > 0))
119        {
120            ALOGD ("%s: data size=%u", __FUNCTION__, data.size());
121            if (checksum == crcChecksumCompute ((const unsigned char*) data.data(), data.size()))
122                isGood = TRUE;
123            else
124                ALOGE ("%s: checksum mismatch", __FUNCTION__);
125        }
126        else
127            ALOGE ("%s: invalid length", __FUNCTION__);
128    }
129    else
130        isGood = TRUE; //assume file does not exist
131    return isGood;
132}
133