Question

我正在尝试获取连接到服务器套接字的IP和客户端端口。我传递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于248.127.0.0:24870的内容...... 我做错了什么？

PS返回的地址长度为16.函数返回的结果为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

在致电addressLength之前，您忘了设置getpeername。你需要：

addressLength = sizeof(address);

正如文件所说：

如果提供的缓冲区太小，则会截断返回的地址

Answer 2

您需要将完整的sockaddr_in实例传递给getpeername()而不是sockaddr实例，并且需要在调用addressLength之前设置getpeername()：

void SocketServer::Log ( int socketFD , string message )       
{       
    struct sockaddr_in                  address = {0};       
    socklen_t                           addressLength = sizeof(address);       
    string                              ip;       
    int                                 port;       

    int result = getpeername ( socketFD , (struct sockaddr*) &address , &addressLength );       
    cout << "Address length is " << addressLength << "     Return is " <<  result << endl;       

    ip = inet_ntoa ( address.sin_addr );       
    port = ntohs ( address.sin_port );       

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

C ++ getpeername返回0.0.0.0:0

2 个答案: