Re: [lwip-devel] Lost segments in tcp_receive

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Åke Rehnman wrote:
> The other end is windows xp...
>
> I did test to change it to rcv_ann_wnd-1 and it works as well as the 
> 64*TCP_MSS.
>
> The thing is that this problem only shows when I'm loosing packets (I'm 
>   

Whether you are loosing packets or not, the remote side still should 
only send packets that are inside the window. And I assume windows does 
this. The fact that you don't get errors when rcv_ann_wnd is used for 
the comparision and that it is sometimes bigger than rcv_wnd suggests a 
bug in the calculation of the two. Could you file a bug report on 
savannah? Attaching packet captures of such a situation could be worthy 
as well (so that we can see the packets sent by windows are in a valid 
range inside the receive window).

> currently testing the microblaze port by removing every 1000'nd input 
> packet). And when lwip does loose packets this way windows starts a flood of 
> retransmissions and often grinds to total stall. And I did check the stats 
> and I'm not running out of resources.
>   

A total stall seems strange. Maybe a packet capture can help here, too...

Simon