Re: [lwip-users] netconn_connect returns OK when connection refused?

[address@hidden]

Am 21.01.2022 um 15:37 schrieb Grant Edwards:
> On 2022-01-20, Grant Edwards <grant.b.edwards@gmail.com> wrote:
>
> > I'm running into a problem where netconn_connect always returns OK
> > immediately, even when the connection was refused by the server (it
> > replies to the SYN with a RST). Subsequent attempts to write to the
> > connection return -14 (ERR_RST) or -11 (ERR_CONN).
> >
> > Shouldn't netconn_connect() return an error if the connection was
> > refused?  If the server accepts the conneciton, it seems to work OK.
>
> There's actually another strange netconn_connect() behavior I've
> noticed. I have a test app with 4 client threads that repeatedly
> connect to a server, exchange data for a few seconds, then disconnect.
>
> The first three threads that call netconn_connect() get error codes
> 2,3,4 (always in that order).

I'm not sure what you mean here. err_t error codes should be negative.
With "2,3,4", do you mean ERR_BUF, ERR_TIMEOUT, ERR_RTE? That would be
strange.

Regards,
Simon

> The fourth thread always connects and
> returns OK.  A couple seconds later, the first three connect
> OK. Subsequent connects always work.
>
> Obvserving the network traffic for the three "failures" show that the
> SYN/SYN-ACK/ACK handshake was completed, then the lwIP side
> immediately closed the connection with a FIN.
>
> Any ideas on what would cause that sort of behavior?
>
>
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