Question

我有一个通过以太网广播的设备，使用下面的代码成功接收了数据包。设备还通过WiFi单播相同的数据包，但未收到此消息（在Windows中禁用除WiFi之外的所有其他接口，我收到超时错误）。如果我更改：

address.sin_addr.s_addr = htonl(INADDR_ANY);

到

address.sin_addr.s_addr = inet_addr("192.168.0.13");

它确实是接收数据包的wifi接口的地址。在WireShark中可以看到通过以太网和WiFi传输的数据包，它们之间的唯一区别是目标地址（广播和单播）和ttl。

代码如下：

int main()
{
    int iResult;
    char recv_buf[4000];
    int opt = 1;
    WORD wVersionRequested;
    WSADATA wsaData;
    int err;

    wVersionRequested = MAKEWORD(2, 2);

    err = WSAStartup(wVersionRequested, &wsaData);
    if (err != 0) {
        printf("WSAStartup failed with error: %d\n", err);
        return 1;
    }

    SOCKET handle = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

    int return_code = 0;

    return_code = setsockopt(handle, SOL_SOCKET, SO_REUSEADDR, reinterpret_cast<char *>(&opt), sizeof(opt));

    std::cout<<"socket option 1 return:" << return_code << std::endl;

    DWORD tv = 100;
    return_code = setsockopt(handle, SOL_SOCKET, SO_RCVTIMEO, reinterpret_cast<char *>(&tv), sizeof(tv));

    std::cout << "socket option 2 return:" << return_code<< std::endl;

    sockaddr_in address;
    address.sin_family = AF_INET;
    address.sin_port = htons(3000);
    address.sin_addr.s_addr = htonl(INADDR_ANY);
    //address.sin_addr.s_addr = inet_addr("192.168.0.13"); //this works
    memset(&address.sin_zero, 0, sizeof(address.sin_zero));

    std::cout << "bind return:" <<  bind(handle, (const sockaddr *)&address, sizeof(sockaddr_in)) << std::endl;

    // Receive data until the server closes the connection
    do {
        Sleep(5000);
        iResult = recv(handle, recv_buf, 4000, 0);
        if (iResult > 0)
            printf("Bytes received: %d\n", iResult);
        else if (iResult == 0)
            printf("Connection closed\n");
        else
            printf("recv failed: %d\n", WSAGetLastError());
    } while (true);

    return 0;
}

无法使用INADDR_ANY通过WiFi接收UNICAST数据包

0 个答案: