Re: [lwip-devel] Limiting the number of connections per listening socket by queuing syn requests

[Frédéric BERNON]

What is the advantage on with the listen's backlog feature ?

----- Original Message ----- 
From: "Tobias Wegner" <address@hidden>
To: <address@hidden>
Sent: Sunday, May 04, 2008 2:23 PM
Subject: [lwip-devel] Limiting the number of connections per listening 
socket by queuing syn requests


> Hi everyone!
>
> I am using lwip 1.3.0 on an embedded webserver with very limited resources 
> (ARM7, 64 kb RAM) and had problems with programs which are using more than 
> one single connection. Because my webserver only uses a single processing 
> thread, incoming request are only processed one after each other. In 
> combination with the few RAM this causes some kind of deadlock because 
> unprocessed incoming data blocks the buffer space and by that the 
> currently active HTTP connection, so that this connection cannot be 
> finished and the buffers are never freed again.
>
> As a measure against this I implemented a queue for the listening port 
> where the answers to incoming syn requests are hold back until there is no 
> connection to the listening port open anymore. In my specific application 
> this allows me to handle 8 concurrent connections sequentially without any 
> problems.
>
> First I would like to ask you if you think this is a proper solution and 
> second if you are interested in my patch.
>
> Regards,
> Tobias Wegner
>
>
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