Re: [ECOS] TCP Transactions

[Matt Jerdonek <maj1224@yahoo.com>]

--- Andrew Lunn <andrew@lunn.ch> wrote:
> On Mon, Oct 20, 2003 at 04:27:11PM -0700, Matt
> Jerdonek wrote:
> > Hello again,
> > 
> > I'm developing an application that sends small
> > transactions via TCP.  The basic flow is 1) Bring
> up
> > the connection 2) Send request 3) Get response 4)
> > Bring down the connection.  Simple enough ...
> > 
> > But, when running any volume of transactions, all
> my
> > socket file descriptors get stuck in TIME_WAIT
> state. 
> > When this occurs, my application is effectively
> > disabled until a file descriptor times out.
> 
> Is this the client or the server end that has the
> problem?
> 
> Are you doing a setsocketopt() for SO_REUSEADDR?
> 
> 
>     Andrew
> 
Andrew,

Thanks for the reply.  My code is the client end of
the connection.  Initially, my code was a call only to
socket() and a call to connect().  I changed it to a
call to socket(), setsockopt(REUSEADDR),
setsockopt(REUSEPORT), bind(), and connect().  In both
cases,  it failed.  Please look at the following code
from bsd_tcpip/ver/src/sys/netinet/tcp_usrreq.c
-------------------------------------
/*
 * Cannot simply call in_pcbconnect, because there
 * might be an
 * earlier incarnation of this same connection still
in
 * TIME_WAIT state, creating an ADDRINUSE error.
 */
oinp = in_pcblookup_hash(...);
if (oinp) {
	if (...RFC1644 check...)
	        otp = tcp_close(otp);
	else
		return EADDRINUSE;
	} 
-----------------------------------
I think I have to find a method to shorten the
TIME_WAIT state.  The TIME_WAIT state is defined as 2
* MSL (or 60 seconds).  If I make the MSL
configurable, I can shorten the TIME_WAIT.  Is this
reasonable?

Thanks,
-- Matt


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