windows 设置网卡接受组播 win32 socket 代码例子

以下是一个简单的Win32 Socket代码示例，用于在Windows上设置网卡以接受组播消息：

#include <WinSock2.h>
#include <WS2tcpip.h>
#include <iostream>

#pragma comment(lib, "Ws2_32.lib")

int main() {
    // 初始化 Winsock
    WSADATA wsaData;
    int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (iResult != 0) {
        std::cerr << "WSAStartup failed: " << iResult << std::endl;
        return 1;
    }

    // 创建套接字
    SOCKET socketFd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (socketFd == INVALID_SOCKET) {
        std::cerr << "socket creation failed: " << WSAGetLastError() << std::endl;
        WSACleanup();
        return 1;
    }

    // 允许多个套接字绑定到同一地址
    BOOL bOptVal = TRUE;
    iResult = setsockopt(socketFd, SOL_SOCKET, SO_REUSEADDR, (char*)&bOptVal, sizeof(BOOL));
    if (iResult == SOCKET_ERROR) {
        std::cerr << "setsockopt SO_REUSEADDR failed: " << WSAGetLastError() << std::endl;
        closesocket(socketFd);
        WSACleanup();
        return 1;
    }

    // 绑定套接字到本地地址
    sockaddr_in localAddr;
    localAddr.sin_family = AF_INET;
    localAddr.sin_port = htons(12345); // 绑定到本地端口12345
    localAddr.sin_addr.s_addr = INADDR_ANY;
    iResult = bind(socketFd, (sockaddr*)&localAddr, sizeof(localAddr));
    if (iResult == SOCKET_ERROR) {
        std::cerr << "bind failed: " << WSAGetLastError() << std::endl;
        closesocket(socketFd);
        WSACleanup();
        return 1;
    }

    // 加入多播组
    ip_mreq mreq;
    inet_pton(AF_INET, "239.255.255.250", &mreq.imr_multiaddr.s_addr); // 组播组地址
    mreq.imr_interface.s_addr = INADDR_ANY; // 本地接口地址
    iResult = setsockopt(socketFd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char*)&mreq, sizeof(ip_mreq));
    if (iResult == SOCKET_ERROR) {
        std::cerr << "setsockopt IP_ADD_MEMBERSHIP failed: " << WSAGetLastError() << std::endl;
        closesocket(socketFd);
        WSACleanup();
        return 1;
    }

    // 接收数据
    char buf[1024];
    sockaddr_in remoteAddr;
    int addrLen = sizeof(remoteAddr);
    iResult = recvfrom(socketFd, buf, sizeof(buf), 0, (sockaddr*)&remoteAddr, &addrLen);
    if (iResult == SOCKET_ERROR) {
        std::cerr << "recvfrom failed: " << WSAGetLastError() << std::endl;
        closesocket(socketFd);
        WSACleanup();
        return 1;
    }

    // 处理接收到的数据
    std::cout << "Received " << iResult << " bytes from " << inet_ntoa(remoteAddr.sin_addr) << std::endl;
    std::cout << "Data: " << buf << std::endl;

    // 关闭套接字
    closesocket(socketFd);
    WSACleanup();
    return 0;
}

在上面的示例中，我们创建了一个UDP套接字并将其绑定到本地地址和端口。然后，我们使用`setsockopt`函数将其加入到组播组中。最后，我们使用`recvfrom`函数接收来自组播组的数据包。注意，你需要将组播地址和本地接口地址替换为你需要的地址。