确定客户端绑定的TCP端口号

I create a TCP socket without bothering about the port number to bind to [socket.sin_port = 0]. However later on if I want to print the port number of client how do I do that? The client C application (on Linux) creates many clients which get connected to server. To debug issues I capture the traffic on ethereal. I thought of printing the port number in logs while issue arises so that filtering on ethereal becomes easy. I create a TCP socket without bothering about t