Re: [lwip-devel] A pcb stall in the FIN_WAIT_1

[Simon Goldschmidt]

narke <address@hidden> wrote:
> In my system, I closed a passive connected PCB and before that the
> network cable was plugged out.  Then FIN_WAIT_1 pcb continuously to
> send FIN segments.  Because this pcb stays in active_pcb list, I
> cannot bind another pcb on the same port.  (I've already waited for
> more than 2*MSL time)
> 
> My question is, in this state, how long time the FIN_WAIT_1 pcb can be
> released?

In any state (except for SYN_SENT), the maximum number of retransmissions is 
configured by TCP_MAXRTX (which is 12 by default). As there is an exponential 
backoff (see tcp_backoff[] values), 2*MSL is of course not enough to just abort 
a connection, as the default values of TCP are very fault-tolerant.

> And, in this case, does the tcp_abort() helpful?

You can of course abort the previous connection manually, but letting the 
listening pcb always be bound (so you don't have to rebind) would be a better 
idea, I guess.

Simon
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