Tcp_listen, who am i connected to ?

When creating a TCP listener, and a connection is made i want to know who’s IP and Mac# has made the connection to me.
I did a little looking around and found a function called “psocket( sock_type *s )”. In there is this: "puts( inet_ntoa( buffer, s->tcp.hisaddr) ); "

Now i did a quite a bit of searching and could find nothing in the docs for “hisaddr”. What other parameters are available and why is this not documented ?