RE: [lwip-users] TCP client side problems using netconn api

[Kieran Mansley]

On Wed, 2009-04-15 at 22:36 -0400, Ben Bobbitt wrote:
> Here's the pcap file from wireshark.  If you look, you can see a few 
> successful tcp sessions that close without issue and then in frame 158 you'll 
> see the ack sequence issue and the resulting FIN, ACK retries repeatedly from 
> the server.
> 
> In capturing this for you, I notice that I did not correctly report that the 
> Client FIN, ACK is also the wrong (?) seq number, not as I wrote below, but:
> 
> Server  FIN, ACK   seq 433 ack 70
> Client   ACK       seq 70  ack 433     < - note the ack # is == seq prior
> Client   FIN, ACK  seq 70  ack 433 <--- this seq is still 433
> Server ACK         seq 434 ack 71

OK, looking at the packet capture that is definitely wrong.  The stack
never acks the FIN sent by the server, despite repeated retransmission.

I recommend you file a bug for this on savannah so that it doesn't get
forgotten.  If you debug what is happening as David Empson suggests,
that would be a great help.

For a reference to how the netconn api should be used, I guess the
socket API is one major user of it, but not sure if that helps.

Kieran