Subject: Re: TCP timeout mechanism

From: Proneet Biswas <[email-masked]>
Date: Fri, 04 Aug 2000 12:07:09 -0700

Hi Alan,
 I am sorry I had not been very specific. The device I intend to support is
kind of a firewall which does not have a stack on it. It will create the
session entries based on the packets which flow through it ot other machines.
SO, it is the internal data structures which I need to clear. To put it a
different fashion :

There is a cache to which I add entries whenever a new session starts. The
problem is identifying the sessions in the cache which have timed out without
using a timer thread to go through all the entries.

Thanks.
Proneet.

Alan Cox wrote:

> Track state (remembering to allow for unreliability/retransmits) and also
> generate faked probe acks _very_ carefully and with backoffs to test if the
> socket has died after a timeout.
>
> Hardly rocket science.
>
> Once ipsec is standard you won't be much able to session track anything tho

---

From: Alan Cox <[email-masked]>
Date: Fri, 4 Aug 2000 23:55:27 +0100 (BST)

> using a timer thread to go through all the entries.

You cannot do that without generating frames and tracking the packets
Thats TCP, thats how it works. You dont need a TCP stack but you need to follow
the tcp sequence space and the like

Alan