Closing a listening TCP socket in C

Question

Suppose you have a socket listening on a TCP port, and some clients are connected. When one issues sock_close(fd) in C and tries to bind again on the same port, binding fails. Some TIME_WAIT state is seen on the "netstat -plutnoa" such as:

tcp        0      0 127.0.0.1:4567          127.0.0.1:32977         TIME_WAIT   -                timewait (17.12/0/0)

So how one can properly disconnect the server socket and reconnect on the same port immediately?

Answer 1

You want to use the SO_REUSEADDR option on the socket. The relevant manpage is socket(7). Here's an example of its usage. This question explains what happens.