如何获取接受的入站套接字的 IP 地址？

我的问题是：

服务器将创建一个套接字，绑定到给定端口并使用地址 = INADDR_ANY。

监听（）和接受（）新连接。然后，我们可以获取客户端的ip地址

来自接受（）。

现在，我想知道服务器的IP地址，因为服务器的主机有

上面有多个网卡。

如何知道接受的入站套接字来自的网络接口的 IP 地址？

我尝试了 getsockname，它给了我端口号，但 ip 全部为零。

更新：这是代码：

Server.c（头文件已删除）

int main(void)
{

    struct sockaddr_in stSockAddr;
    int res, addr_len, SocketFD, ConnectFD;

    struct sockaddr_in addr;

    SocketFD = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);

    if(-1 == SocketFD)
    {
      perror("can not create socket");
      //exit(EXIT_FAILURE);
      return -1;
    }

    memset(&stSockAddr, 0, sizeof stSockAddr);
    stSockAddr.sin_family = AF_INET;
    stSockAddr.sin_port = htons(49335);
    stSockAddr.sin_addr.s_addr = INADDR_ANY;

    if(-1 == bind(SocketFD,(struct sockaddr *)&stSockAddr, sizeof stSockAddr))
    {
      perror("error bind failed");
      close(SocketFD);
     return -1;
    }


    printf("going to listen!\n"); 
    if(-1 == listen(SocketFD, 10))
    {   
      perror("error listen failed");
      close(SocketFD);
      //exit(EXIT_FAILURE);
      return -1; 
    }   

    ConnectFD = accept(SocketFD, NULL, NULL);

        if(0 > ConnectFD)
        {   
                perror("error accept failed");
                close(SocketFD);
                //exit(EXIT_FAILURE);
                return -1; 
        }   

    addr.sin_family = AF_INET;
    res = getsockname (ConnectFD, (struct sockaddr *)&addr, &addr_len);
    // if you remove the following comment, that means, if you call 
    // two times of getsockname, the result will be correct.
    //res = getsockname (ConnectFD, (struct sockaddr *)&addr, &addr_len);

    printf("addr:%x\n", addr.sin_addr.s_addr);

    while(1) {
        if (getchar() == 'q')
                        break;
    }

    close(ConnectFD);
    close(SocketFD);
    return 0;
}

下面是client.c：

int main(void)
{

    struct sockaddr_in stSockAddr;

    int Res;

    int SocketFD = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);

    if (-1 == SocketFD)
    {
      perror("cannot create socket");
      exit(EXIT_FAILURE);
    }

    memset(&stSockAddr, 0, sizeof stSockAddr);

    stSockAddr.sin_family = AF_INET;
    stSockAddr.sin_port = htons(49335);
    Res = inet_pton(AF_INET, "192.168.1.102", &stSockAddr.sin_addr);

    if (0 > Res)
    {
      perror("error: first parameter is not a valid address family");
      close(SocketFD);
      exit(EXIT_FAILURE);
    }
    else if (0 == Res)
    {
      perror("char string (second parameter does not contain valid ipaddress");
      close(SocketFD);
      exit(EXIT_FAILURE);
    }

    if (-1 == connect(SocketFD, (struct sockaddr *)&stSockAddr, sizeof stSockAddr))
    {
      perror("connect failed");
      close(SocketFD);
      exit(EXIT_FAILURE);
    }

    /* perform read write operations ... */
    printf("client sockfd is successful\n"); 

      while(1) {

          if (getchar() == 'q')
              break;

      }


    shutdown(SocketFD, SHUT_RDWR);

    close(SocketFD);
    return 0;
}

Use getsockname(2)在从返回的套接字上accept(2), not返回的套接字bind(2).