Given a filedescriptor, how can I find source IP??

[Guy Harris]

>It turns out that in SunOS3.x, inetd by default passed the ip address
>as a command line arg to in.telnetd. 
>
>In SunOS4.1 they "fixed" it so that it does not.

More correctly, in SunOS 4.*0* they picked up the 4.3BSD "inetd", which
handed you a socket for the connection on file descriptors 0, 1, and 2,
and didn't hand you the IP address as a command-line argument.