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Yahan Zhoub7f09082016-03-10 11:45:02 -08001/*
2* Copyright (C) 2016 The Android Open Source Project
3*
4* Licensed under the Apache License, Version 2.0 (the "License");
5* you may not use this file except in compliance with the License.
6* You may obtain a copy of the License at
7*
8* http://www.apache.org/licenses/LICENSE-2.0
9*
10* Unless required by applicable law or agreed to in writing, software
11* distributed under the License is distributed on an "AS IS" BASIS,
12* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13* See the License for the specific language governing permissions and
14* limitations under the License.
15*/
16
Jason Macnakd54a5352023-12-08 01:21:48 +000017#include "gfxstream/guest/ChecksumCalculator.h"
Yahan Zhoub7f09082016-03-10 11:45:02 -080018
Yahan Zhoub7f09082016-03-10 11:45:02 -080019#include <string.h>
20
Jason Macnakd54a5352023-12-08 01:21:48 +000021namespace gfxstream {
22namespace guest {
23
Yahan Zhoub7f09082016-03-10 11:45:02 -080024// Checklist when implementing new protocol:
25// 1. update CHECKSUMHELPER_MAX_VERSION
Yurii Zubrytskyiac0e8ca2016-11-04 11:57:02 -070026// 2. update ChecksumCalculator::Sizes enum
Yahan Zhoub7f09082016-03-10 11:45:02 -080027// 3. update checksumByteSize()
28// 4. update addBuffer, writeChecksum, resetChecksum, validate
29
30// change CHECKSUMHELPER_MAX_VERSION when you want to update the protocol version
31#define CHECKSUMHELPER_MAX_VERSION 1
32
Yahan Zhoub7f09082016-03-10 11:45:02 -080033// utility macros to create checksum string at compilation time
34#define CHECKSUMHELPER_VERSION_STR_PREFIX "ANDROID_EMU_CHECKSUM_HELPER_v"
35#define CHECKSUMHELPER_MACRO_TO_STR(x) #x
36#define CHECKSUMHELPER_MACRO_VAL_TO_STR(x) CHECKSUMHELPER_MACRO_TO_STR(x)
37
38static const uint32_t kMaxVersion = CHECKSUMHELPER_MAX_VERSION;
39static const char* kMaxVersionStrPrefix = CHECKSUMHELPER_VERSION_STR_PREFIX;
40static const char* kMaxVersionStr = CHECKSUMHELPER_VERSION_STR_PREFIX CHECKSUMHELPER_MACRO_VAL_TO_STR(CHECKSUMHELPER_MAX_VERSION);
41
42#undef CHECKSUMHELPER_MAX_VERSION
43#undef CHECKSUMHELPER_VERSION_STR_PREFIX
44#undef CHECKSUMHELPER_MACRO_TO_STR
45#undef CHECKSUMHELPER_MACRO_VAL_TO_STR
46
47uint32_t ChecksumCalculator::getMaxVersion() {return kMaxVersion;}
48const char* ChecksumCalculator::getMaxVersionStr() {return kMaxVersionStr;}
49const char* ChecksumCalculator::getMaxVersionStrPrefix() {return kMaxVersionStrPrefix;}
50
51bool ChecksumCalculator::setVersion(uint32_t version) {
52 if (version > kMaxVersion) { // unsupported version
53 LOG_CHECKSUMHELPER("%s: ChecksumCalculator Set Unsupported version Version %d\n",
54 __FUNCTION__, m_version);
55 return false;
56 }
57 if (m_isEncodingChecksum) { // setVersion is called in the middle of encoding checksums
58 LOG_CHECKSUMHELPER("%s: called between addBuffer and writeChecksum\n",
59 __FUNCTION__);
60 return false;
61 }
62 m_version = version;
63 LOG_CHECKSUMHELPER("%s: ChecksumCalculator Set Version %d\n", __FUNCTION__,
64 m_version);
65 return true;
66}
67
68size_t ChecksumCalculator::checksumByteSize() const {
69 switch (m_version) {
70 case 0:
71 return 0;
72 case 1:
73 return sizeof(uint32_t) + sizeof(m_numWrite);
74 default:
75 return 0;
76 }
77}
78
Yahan Zhoud9069282016-06-17 17:40:14 -070079ChecksumCalculator::ChecksumCalculator()
80 : m_version(0)
81 , m_numRead(0)
82 , m_numWrite(0)
83 , m_isEncodingChecksum(false)
84 , m_v1BufferTotalLength(0)
85{
86}
87
Lingfeng Yang764a1fc2019-08-22 12:16:11 -070088void ChecksumCalculator::addBuffer(const void*, size_t packetLen) {
Yahan Zhoub7f09082016-03-10 11:45:02 -080089 m_isEncodingChecksum = true;
90 switch (m_version) {
91 case 1:
92 m_v1BufferTotalLength += packetLen;
93 break;
94 }
95}
96
97bool ChecksumCalculator::writeChecksum(void* outputChecksum, size_t outputChecksumLen) {
98 if (outputChecksumLen < checksumByteSize()) return false;
99 char *checksumPtr = (char *)outputChecksum;
100 switch (m_version) {
101 case 1: { // protocol v1 is to reverse the packetLen and write it at the end
Yahan Zhoue222fd52016-03-16 12:41:08 -0700102 uint32_t val = computeV1Checksum();
Yahan Zhoub7f09082016-03-10 11:45:02 -0800103 memcpy(checksumPtr, &val, sizeof(val));
104 memcpy(checksumPtr+sizeof(val), &m_numWrite, sizeof(m_numWrite));
105 break;
106 }
107 }
108 resetChecksum();
Yahan Zhoub7f09082016-03-10 11:45:02 -0800109 m_numWrite++;
110 return true;
111}
112
113void ChecksumCalculator::resetChecksum() {
114 switch (m_version) {
115 case 1:
116 m_v1BufferTotalLength = 0;
117 break;
118 }
119 m_isEncodingChecksum = false;
120}
121
Yahan Zhoue222fd52016-03-16 12:41:08 -0700122bool ChecksumCalculator::validate(const void* expectedChecksum, size_t expectedChecksumLen) {
123 size_t checksumSize = checksumByteSize();
124 if (expectedChecksumLen != checksumSize) {
125 m_numRead++;
126 resetChecksum();
127 return false;
128 }
Yurii Zubrytskyiac0e8ca2016-11-04 11:57:02 -0700129 bool isValid;
Yahan Zhoub7f09082016-03-10 11:45:02 -0800130 switch (m_version) {
131 case 1: {
Yurii Zubrytskyiac0e8ca2016-11-04 11:57:02 -0700132 const uint32_t val = computeV1Checksum();
133 isValid = 0 == memcmp(&val, expectedChecksum, sizeof(val)) &&
134 0 == memcmp(&m_numRead,
135 static_cast<const char*>(expectedChecksum) +
136 sizeof(val),
137 sizeof(m_numRead));
138
Yahan Zhoub7f09082016-03-10 11:45:02 -0800139 break;
140 }
Yurii Zubrytskyiac0e8ca2016-11-04 11:57:02 -0700141 default:
142 isValid = true; // No checksum is a valid checksum.
143 break;
Yahan Zhoub7f09082016-03-10 11:45:02 -0800144 }
Yahan Zhoub7f09082016-03-10 11:45:02 -0800145 m_numRead++;
Yahan Zhoue222fd52016-03-16 12:41:08 -0700146 resetChecksum();
Yahan Zhoub7f09082016-03-10 11:45:02 -0800147 return isValid;
148}
149
Yahan Zhoue222fd52016-03-16 12:41:08 -0700150uint32_t ChecksumCalculator::computeV1Checksum() {
151 uint32_t revLen = m_v1BufferTotalLength;
Yahan Zhoub7f09082016-03-10 11:45:02 -0800152 revLen = (revLen & 0xffff0000) >> 16 | (revLen & 0x0000ffff) << 16;
153 revLen = (revLen & 0xff00ff00) >> 8 | (revLen & 0x00ff00ff) << 8;
154 revLen = (revLen & 0xf0f0f0f0) >> 4 | (revLen & 0x0f0f0f0f) << 4;
155 revLen = (revLen & 0xcccccccc) >> 2 | (revLen & 0x33333333) << 2;
156 revLen = (revLen & 0xaaaaaaaa) >> 1 | (revLen & 0x55555555) << 1;
157 return revLen;
158}
Jason Macnakd54a5352023-12-08 01:21:48 +0000159
160} // namespace guest
Joshua Duongd2b8f0c2024-02-07 21:20:32 +0000161} // namespace gfxstream