C++ Socket庫處理IP地址沖突

在C++中處理IP地址沖突，通常需要使用套接字編程庫（如socket library）和網絡編程技術。以下是一個簡單的示例，展示了如何使用C++處理IP地址沖突：

1. 首先，創建一個套接字并綁定到本地IP地址和端口：

#include <iostream>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h>

int main() {
    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) {
        std::cerr << "Error creating socket" << std::endl;
        return 1;
    }

    struct sockaddr_in server_addr;
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = htonl(INADDR_ANY); // Bind to all available IP addresses
    server_addr.sin_port = htons(8080);

    if (bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        std::cerr << "Error binding socket" << std::endl;
        close(sockfd);
        return 1;
    }

    // Listen for incoming connections
    if (listen(sockfd, 5) < 0) {
        std::cerr << "Error listening on socket" << std::endl;
        close(sockfd);
        return 1;
    }

    // Accept incoming connection
    struct sockaddr_in client_addr;
    socklen_t client_addr_len = sizeof(client_addr);
    int client_sockfd = accept(sockfd, (struct sockaddr *)&client_addr, &client_addr_len);
    if (client_sockfd < 0) {
        std::cerr << "Error accepting connection" << std::endl;
        close(sockfd);
        return 1;
    }

    // Handle the client connection
    // ...

    // Close the sockets
    close(client_sockfd);
    close(sockfd);

    return 0;
}

2. 為了檢測和處理IP地址沖突，您需要監聽網絡中的所有可用網絡接口。這可以通過遍歷/sys/class/net目錄并檢查每個接口的IP地址來實現。以下是一個示例：

#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>

std::vector<std::string> get_local_ip_addresses() {
    std::vector<std::string> ip_addresses;
    std::ifstream ifs("/sys/class/net");
    std::string line;

    while (std::getline(ifs, line)) {
        std::ifstream iface_file("/sys/class/net/" + line + "/address");
        if (iface_file.is_open()) {
            std::string ip;
            if (std::getline(iface_file, ip)) {
                ip_addresses.push_back(ip);
            }
            iface_file.close();
        }
    }

    return ip_addresses;
}

int main() {
    // Get local IP addresses
    std::vector<std::string> local_ip_addresses = get_local_ip_addresses();

    // Create and bind socket
    // ...

    // Listen for incoming connections
    // ...

    // Accept incoming connection
    // ...

    // Handle the client connection
    // For example, you can send an IP address conflict message to the client
    std::string conflict_message = "IP address conflict detected!";
    send(client_sockfd, conflict_message.c_str(), conflict_message.length(), 0);

    // Close the sockets
    close(client_sockfd);
    close(sockfd);

    return 0;
}

請注意，這個示例僅用于演示目的，實際應用中可能需要更復雜的邏輯來處理IP地址沖突。在實際項目中，您可能需要使用更高級的網絡庫（如Boost.Asio）來處理這些任務。