[lwip-users] Window memory leak from retransmitted packets

[David Ward]

Hi
I wonder if anyone can help with a lwip problem on a Xilinx ML506  
Virtex 5 evaluation board with a microblaze processor and Xilinx Lwip  
2.0

We are using the raw packet implemetation with a single TCPIP socket  
link between a windows PC and the development board. I have based my  
code on the Xilinx web server examples.

Our link connects and runs for a while, then fails.
Investigating with wireshark shows that on occasion lwip fails to ack  
a packet or two causing the PC to perform a fast re-transmission, lwip  
transmits an ack and the link re covers, except that our window size  
has reduced by the size of the re-transmitted packet. It is this  
'window buffer leak' that causes the link to fail eventually.

Is there anything I am missing, or that I need to do to clear out  
duplicate packets?

Many thanks in advance for your help

Dave




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