Re: [lwip-users] Refusing an incoming connection on a listening port

[Jonathan Larmour]

Antonio de Angelis wrote:
> Hi all,
>
> I am working with the Win32 port. My question is, when i create a 
> listening server on a specific port, how can I refuse an incoming 
> connection on that port? For example, if I want to refuse the connection 
> from a specific remote IP address,

lwIP does not have the ability to selectively only establish certain TCP 
connections and not others. So you won't be able to selectively have 
"connection refused" sent to an unwanted remote IP.

But there's nothing stopping you immediately closing the connection as 
soon as a connection was accepted, after you've looked at who the peer 
address is. That's probably good enough.

> or if i want to refuse the connection 
> in case that there are too much active connections on the server. Thank you

That case is different - denying everybody, rather than denying 
selectively. In which case you could temporarily remove your listening 
socket entirely. However because lwIP doe snot have SOREUSEADDR, it's 
probably safer not to, otherwise you might have difficulty recreating the 
socket reliably when things are back to normal again. So again maybe it's 
still better to just close unwanted connections after they're accepted.

Jifl
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