Re: Re: Re: Re: [lwip-users] Re: tx badnwidth

[Chen]

OK, I track deeper in the source

The reason lwip_recv still blocks even the flag says NOWAIT is because
that
sock->rcvevent
is Non-zero. Yet, at this point, all incoming TCP packets have been
received, the only extra packets are those tcp window updating packets,
which should not increase the rcvevent for TCP connection. 

Since
sock->rcvevent
is not zero, lwip_recv calls
netconn_recv to fetch the data, yet, there is no data, so it waits there
until connection is closed or something comes in.

I believe lwIP has a problem here

Capture file:
http://www.dataq.com/chen/new.cap

Thanks

>>>>>>>>>>



> The program is supposed to send out
> data continuously once the connection 
> is made.
>
> With telnet, Wireshark will not capture these tcp window updating
> packets, 
> and the program works as expected.
>
> With a 3rd-party telnet-like program, which I am trying to investigate
> more, Wireshark will capture these tcp window updating packets, and the
> lwip will stay in the call to nbytes=lwip_recv(clientfd, buffer, 
> sizeof(buffer),8), and won't get out of it until I close the connection,
> even though the flag for lwip_recv is NOWAIT.
>
> nbytes=lwip_recv(clientfd, buffer, sizeof(buffer),8) is also called in
> the 
> above telnet case, and it will not block the process
>
> Thanks