Re: [lwip-devel] Potential bug in tcp_close 1.4.2 rc1

[Kieran Mansley]

On Thu, 2011-03-24 at 15:46 -0600, Brent Kucera wrote:
> 
> You are correct, the problem is that when I shut down the server
> (calling
> echo_close, which calls tcp_close), then restart the server, tcp_bind
> fails
> with ERR_USE.I think it shouldn't because if I close a connection,
> that port
> ought to be free regardless of what the other side does.

I think the current behaviour might be correct, but I don't have the
time today to check to be sure.  The side of the connection that does
the close first will take longer to get to a point where the port can be
re-used.  This is a consequence of the TCP state machine and the way it
is careful to avoid packets from an earlier connection being interpreted
as for a new connection.  I think SO_REUSE is the right thing to do.
You might want to check that if you wait a couple of minutes and restart
your server that it is then able to get the port.  This sort of thing
shows itself on other platforms like Linux too.

Kieran