sockets 相关问题

所以我正在搞套接字编程，我写了一个转发代理，其工作原理如下： #包括 #包括 #包括 #包括所以我正在搞套接字编程，我写了一个转发代理，其工作原理如下： #include <winsock2.h> #include <ws2tcpip.h> #include <windows.h> #include <iostream> #include <thread> #pragma comment(lib, "ws2_32.lib") #define BUFFER_SIZE 8192 #define DEFAULT_PORT "87" // Global variables SOCKET g_listenSocket = INVALID_SOCKET; bool g_running = false; bool initWinsock() { WSADATA wsaData; return WSAStartup(MAKEWORD(2, 2), &wsaData) == 0; } bool initServer() { struct addrinfo* result = nullptr, hints; ZeroMemory(&hints, sizeof(hints)); hints.ai_family = AF_INET; hints.ai_socktype = SOCK_STREAM; hints.ai_protocol = IPPROTO_TCP; hints.ai_flags = AI_PASSIVE; if (getaddrinfo(NULL, DEFAULT_PORT, &hints, &result) != 0) { return false; } g_listenSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol); if (g_listenSocket == INVALID_SOCKET) { freeaddrinfo(result); return false; } if (bind(g_listenSocket, result->ai_addr, (int)result->ai_addrlen) == SOCKET_ERROR) { freeaddrinfo(result); closesocket(g_listenSocket); return false; } freeaddrinfo(result); if (listen(g_listenSocket, SOMAXCONN) == SOCKET_ERROR) { closesocket(g_listenSocket); return false; } return true; } bool isConnectMethod(const char* request) { return strncmp(request, "CONNECT", 7) == 0; } void parseHostAndPort(const char* request, char* host, char* port) { char* line = new char[strlen(request) + 1]; strcpy(line, request); if (isConnectMethod(line)) { // Handle CONNECT method (HTTPS) char* start = line + 8; // Skip "CONNECT " char* end = strchr(start, ' '); if (end) { *end = '\0'; char* colon = strchr(start, ':'); if (colon) { *colon = '\0'; strcpy(host, start); strcpy(port, colon + 1); } else { strcpy(host, start); strcpy(port, "443"); } } } else { // Handle HTTP requests bool foundHost = false; char* current = line; char* eol; // Look for Host header while ((eol = strstr(current, "\r\n")) != nullptr) { *eol = '\0'; if (strncmp(current, "Host: ", 6) == 0) { char* hostLine = current + 6; char* colon = strchr(hostLine, ':'); if (colon) { *colon = '\0'; strcpy(host, hostLine); strcpy(port, colon + 1); } else { strcpy(host, hostLine); strcpy(port, "80"); } foundHost = true; break; } current = eol + 2; } // If no Host header found, try to parse from the request line if (!foundHost) { if (strncmp(line, "GET http://", 11) == 0 || strncmp(line, "POST http://", 12) == 0) { char* start = strchr(line, '/') + 2; char* end = strchr(start, '/'); if (end) { *end = '\0'; char* colon = strchr(start, ':'); if (colon) { *colon = '\0'; strcpy(host, start); strcpy(port, colon + 1); } else { strcpy(host, start); strcpy(port, "80"); } } } } } delete[] line; } SOCKET connectToHost(const char* host, const char* port) { struct addrinfo hints = {}, * result = nullptr; hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_STREAM; if (getaddrinfo(host, port, &hints, &result) != 0) { return INVALID_SOCKET; } SOCKET serverSocket = socket(result->ai_family, result->ai_socktype, result->ai_protocol); if (serverSocket == INVALID_SOCKET) { freeaddrinfo(result); return INVALID_SOCKET; } if (connect(serverSocket, result->ai_addr, (int)result->ai_addrlen) == SOCKET_ERROR) { closesocket(serverSocket); freeaddrinfo(result); return INVALID_SOCKET; } freeaddrinfo(result); return serverSocket; } void handleBidirectionalTraffic(SOCKET client, SOCKET server) { fd_set readSet; char buffer[BUFFER_SIZE]; while (true) { FD_ZERO(&readSet); FD_SET(client, &readSet); FD_SET(server, &readSet); // Wait for data on either socket if (select(0, &readSet, NULL, NULL, NULL) == SOCKET_ERROR) { break; } // Check client -> server if (FD_ISSET(client, &readSet)) { int bytes = recv(client, buffer, sizeof(buffer), 0); if (bytes <= 0) break; if (send(server, buffer, bytes, 0) <= 0) break; } // Check server -> client if (FD_ISSET(server, &readSet)) { int bytes = recv(server, buffer, sizeof(buffer), 0); if (bytes <= 0) break; if (send(client, buffer, bytes, 0) <= 0) break; } } closesocket(client); closesocket(server); } void handleClient(SOCKET clientSocket) { char buffer[BUFFER_SIZE]; int bytesReceived = recv(clientSocket, buffer, BUFFER_SIZE - 1, 0); if (bytesReceived <= 0) { closesocket(clientSocket); return; } buffer[bytesReceived] = '\0'; char host[256] = { 0 }; char port[16] = { 0 }; parseHostAndPort(buffer, host, port); if (strlen(host) == 0) { const char* response = "HTTP/1.1 400 Bad Request\r\n\r\n"; send(clientSocket, response, strlen(response), 0); closesocket(clientSocket); return; } SOCKET serverSocket = connectToHost(host, port); if (serverSocket == INVALID_SOCKET) { const char* response = "HTTP/1.1 502 Bad Gateway\r\n\r\n"; send(clientSocket, response, strlen(response), 0); closesocket(clientSocket); return; } if (isConnectMethod(buffer)) { // HTTPS: Send connection established const char* response = "HTTP/1.1 200 Connection established\r\n\r\n"; if (send(clientSocket, response, strlen(response), 0) <= 0) { closesocket(clientSocket); closesocket(serverSocket); return; } } else { // HTTP: Forward the original request if (send(serverSocket, buffer, bytesReceived, 0) <= 0) { closesocket(clientSocket); closesocket(serverSocket); return; } } // Handle bidirectional traffic for both HTTP and HTTPS handleBidirectionalTraffic(clientSocket, serverSocket); } void cleanup() { g_running = false; if (g_listenSocket != INVALID_SOCKET) { closesocket(g_listenSocket); g_listenSocket = INVALID_SOCKET; } WSACleanup(); } int main() { if (!initWinsock()) { std::cerr << "Failed to initialize Winsock\n"; return 1; } if (!initServer()) { std::cerr << "Failed to initialize server\n"; cleanup(); return 1; } g_running = true; std::cout << "Proxy server listening on localhost:87...\n"; while (g_running) { SOCKET clientSocket = accept(g_listenSocket, NULL, NULL); if (clientSocket == INVALID_SOCKET) { continue; } std::cout << "New client connected\n"; // Create a new thread to handle the client std::thread(handleClient, clientSocket).detach(); } cleanup(); return 0; } 程序在循环中使用accept()，为每个连接的客户端创建一个线程，浏览器为每个http请求打开一个tcp连接。现在我想将此代码转换为一个反向代理，它将像这样工作，server.cpp，客户端.cpp。服务器将监听浏览器的连接，接收请求并将其传递给 client.cpp ，其中 client.cpp 将连接到目标主机，然后将响应传递给 server.cpp 然后将响应传递给 browser.client.cpp 将通过以下方式连接简单的 tcp 流到 server.cpp。我的问题是：由于client.cpp/server.cpp将通过一个tcp流进行通信，我如何才能传递所有请求处理它们并将它们发送回server.cpp？，其中server.cpp针对从浏览器有一个线程吗？我的第一个想法是在 client.cpp 中的循环内有一个 recv() ，并为从 server.cpp 发送的每个请求创建一个线程，但问题是我不知道如何将每个响应发送回其server.cpp 中的特定线程。提前致谢。如果您要通过单个连接发送多个数据流，则必须封装每个流中的数据。为此，您可能需要构建数据。也就是说，在代理中读取一些数据，然后在发送到服务器时，添加一点标头，表示后面的 N 字节数据来自流 M。然后在服务器端，你需要有一点一段代码，用于解压数据、单独处理每个流中的数据，并将结果与类似的标头打包在一起，表示以下 N 个字节的回复用于流 M。为了提供一点额外的保证（以及在出现问题时恢复同步的能力），您可能还需要在每帧的开头和结尾添加相当独特的模式。

c++ sockets proxy

回答 1 投票 0

Go 的 netFD.connect Getpeername 检查

投反对票的人请注意：我希望您能为投反对票的人提供一些推理。我问这个问题不是出于好奇，而是因为我在测试中遇到了等待问题。有这段摘录

go sockets network-programming tcp polling

回答 1 投票 0

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