1/*
2 * Copyright (c) 2022 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 *     http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16#ifndef ARKCOMPILER_TOOLCHAIN_WEBSOCKET_HANDSHAKE_HELPER_H
17#define ARKCOMPILER_TOOLCHAIN_WEBSOCKET_HANDSHAKE_HELPER_H
18
19#include "define.h"
20#include "http.h"
21#include "network.h"
22
23#include <array>
24#include <string_view>
25
26namespace OHOS::ArkCompiler::Toolchain {
27class WebSocketKeyEncoder {
28public:
29    // WebSocket Globally Unique Identifier
30    static constexpr std::string_view WEB_SOCKET_GUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
31    // The value of |Sec-WebSocket-Key| header field MUST be a nonce consisting of a randomly selected 16-byte value
32    static constexpr size_t KEY_LENGTH = GetBase64EncodingLength(16);
33    // SHA1 will write SHA_DIGEST_LENGTH == 20 bytes of output
34    static constexpr size_t ENCODED_KEY_LEN = GetBase64EncodingLength(SHA_DIGEST_LENGTH);
35
36    static bool EncodeKey(std::string_view key, unsigned char (&destination)[ENCODED_KEY_LEN + 1]);
37    static bool EncodeKey(const unsigned char(&key)[KEY_LENGTH + 1], unsigned char (&destination)[ENCODED_KEY_LEN + 1]);
38
39private:
40    static bool EncodeKey(const unsigned char *source, size_t length,
41                          unsigned char (&destination)[ENCODED_KEY_LEN + 1]);
42};
43
44class ProtocolUpgradeBuilder {
45public:
46    constexpr size_t CopyStringToBuffer(std::string_view source, size_t startIndex)
47    {
48        for (size_t i = 0, end = source.size(); i < end; ++i, ++startIndex) {
49            upgradeBuffer_[startIndex] = source[i];
50        }
51        return startIndex;
52    }
53
54    template <typename T, size_t LENGTH>
55    constexpr size_t CopyStringToBuffer(const T (&source)[LENGTH], size_t startIndex)
56    {
57        for (size_t i = 0, end = LENGTH - 1; i < end; ++i, ++startIndex) {
58            upgradeBuffer_[startIndex] = source[i];
59        }
60        return startIndex;
61    }
62
63    constexpr ProtocolUpgradeBuilder()
64    {
65        size_t index = CopyStringToBuffer(SWITCHING_PROTOCOLS, 0);
66        index = CopyStringToBuffer(HttpBase::EOL, index);
67        index = CopyStringToBuffer(CONNECTION_UPGRADE, index);
68        index = CopyStringToBuffer(HttpBase::EOL, index);
69        index = CopyStringToBuffer(UPGRADE_WEBSOCKET, index);
70        index = CopyStringToBuffer(HttpBase::EOL, index);
71        index = CopyStringToBuffer(ACCEPT_KEY, index);
72        // will copy key without null terminator
73        index += WebSocketKeyEncoder::ENCODED_KEY_LEN;
74        index = CopyStringToBuffer(HttpBase::EOL, index);
75        index = CopyStringToBuffer(HttpBase::EOL, index);
76    }
77
78    constexpr explicit ProtocolUpgradeBuilder(
79        const unsigned char (&encodedKey)[WebSocketKeyEncoder::ENCODED_KEY_LEN + 1])
80        : ProtocolUpgradeBuilder()
81    {
82        SetKey(encodedKey);
83    }
84
85    constexpr void SetKey(const unsigned char (&encodedKey)[WebSocketKeyEncoder::ENCODED_KEY_LEN + 1])
86    {
87        CopyStringToBuffer(encodedKey, KEY_START);
88    }
89
90    constexpr const char *GetUpgradeMessage()
91    {
92        return upgradeBuffer_.data();
93    }
94
95    static constexpr size_t GetLength()
96    {
97        return MESSAGE_LENGTH;
98    }
99
100private:
101    static constexpr std::string_view SWITCHING_PROTOCOLS = "HTTP/1.1 101 Switching Protocols";
102    static constexpr std::string_view CONNECTION_UPGRADE = "Connection: Upgrade";
103    static constexpr std::string_view UPGRADE_WEBSOCKET = "Upgrade: websocket";
104    static constexpr std::string_view ACCEPT_KEY = "Sec-WebSocket-Accept: ";
105    static constexpr size_t KEY_START = SWITCHING_PROTOCOLS.size()
106        + CONNECTION_UPGRADE.size()
107        + UPGRADE_WEBSOCKET.size()
108        + ACCEPT_KEY.size()
109        + 3 * HttpBase::EOL.size();
110    static constexpr size_t MESSAGE_LENGTH = KEY_START
111        + WebSocketKeyEncoder::ENCODED_KEY_LEN
112        + 2 * HttpBase::EOL.size();
113
114private:
115    // null-terminated string buffer
116    std::array<char, MESSAGE_LENGTH + 1> upgradeBuffer_ {0};
117};
118} // namespace OHOS::ArkCompiler::Toolchain
119
120#endif // ARKCOMPILER_TOOLCHAIN_WEBSOCKET_HANDSHAKE_HELPER_H
121