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

[address@hidden]

Am 20.01.2022 um 17:55 schrieb Grant Edwards:
> 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.

The only way I would think this could happen is if you are using
nonblocking netconns. Normal blocking netconns should wait for the
remote side to ACK the SYN and only then return ERR_OK.

Regards,
Simon

> Here's the relevent code:
>
>
>        conn = netconn_new(NETCONN_TCP);
>        if (!conn)
>          {
>            printf("conn NULL\n");
>            return;
>          }
>        e = netconn_connect(conn, &ip, 7000);
>        if (e != ERR_OK)
>          {
>            printf("%s[%d] netconn_connect e=%d\n",__func__,exinf,e);
>            netconn_delete(conn);
>            return;
>          }
>        printf("connected\n");
>        ...
>            e = netconn_write_partly(conn, data, dsize, NETCONN_COPY, &written);
>            if (e != ERR_OK)
>              printf("%s[%d] netconn_write e=%d\n",__func__,exinf,e);