C++ getpeername 返回 0.0.0.0 :0

Question

我正在尝试获取连接到服务器套接字的客户端的 IP 和端口。我传递了以下函数客户端套接字文件描述符，但它返回 0.0.0.0:0这让我发疯，但有时它会返回类似 248.127.0.0:24870 的内容...我做错了什么？

PS返回地址长度为16，函数返回结果为0，没有错误发生。

void    SocketServer::Log ( int socketFD , string message )
{
    struct sockaddr                     address;
    socklen_t                           addressLength;
    struct sockaddr_in*                 addressInternet;
    string                              ip;
    int                                 port;

    int result = getpeername ( socketFD , &address , &addressLength );
    cout << "Address length is " << addressLength << "     Return is " <<  result << "\n";
    addressInternet = (struct sockaddr_in*)&address;

    ip = inet_ntoa ( addressInternet->sin_addr );
    port = ntohs ( addressInternet->sin_port );

    cout << "Socket FD is " << socketFD << " " << ip << ":" << port << " " <<  message << "\n";
};

Answer 1

在调用 getpeername 之前，您忘记设置 addressLength。你需要:

addressLength = sizeof(address);

正如文档所说:

The returned address is truncated if the buffer provided is too small