Re: [lwip-users] Problem re-opening listening pbc

[address@hidden]

On 14.05.2018 18:27, Keith Rubow wrote:
> [..] I would like to have additional connection
> attempts to be refused. I can achieve this behavior only by closing the
> listening pcb once I reach the max number of connections, but then I
> can't re-open the listening pcb until ALL open connections are closed.
> But some connections might stay open indefinitely, in which case I can
> never open the listening pcb again.

You don't seem to read the responses to your mails. There were two 
suggestsions:
a) do it the standard socket way (even if you are using lwIP callback 
API) and use REUSEADDR to be able to open the listening socket although 
connection sockets are active (or in time-wait; this *is* standard 
behaviour, not an lwIP thing!)
b) play with backlog.

The default usage of backlog is to decrease it when connections are 
actually accepted, but you can just use it to only accept new 
connections after previous connections are closed. To do that, call 
'tcp_backlog_delayed()' in your accept callback and call 
'tcp_backlog_accepted()' when the pcb is closed (when the 'err' callback 
is called, the latter is done internally by the stack).

Simon