[lwip-users] endless loop after window updates

[Andre Puschmann]

Hey folks,
I still have those (at least for me) curious problems with the stack. I
did some more research and figured out a way to turn lwip into kind of
endless loop with only 2 packets every 1500ms.
If I send many packets very quickly to a windows box and then produce
some load on it (e.g. write the received data into a file) windows xp
decreases its receive_wnd with every single ACK. This is o.k. to lwip up
to the certain point where windows resets its receive_window (e.g.
13720bytes .. packet #226 in trace).
lwip now sends as many packets as fit into the new window, which
properly isn't the right behavior, isn't it?
After the following ACK lwip continues bursting out packets regardless
of the seq-no's xp is expecting.
I am still wondering why the whole systems now gets into the this
endless loop with 1 packet per second transfer rate.
It is always the first of two transmitted packets which gets lost, which
seems, at least to me, to be very odd.
Further more, there is no way to "heal" the connection, so far.

Any suggestions what might be the problem or where to pay more attention
to are more than welcome!


I uploaded a trace which shows the described behavior.
bzipped: http://www.puschmann.net/public/stream_with_wnd_update.tar.bz2
(~130k)

unzipped: http://www.puschmann.net/public/stream_with_wnd_update.cap (~300k)



Kind regards


Andre