[lwip-users] TCP checksum error for big sized packets on lwip 1.3.0

[Muhamad Ikhwan Ismail]

Hi,

I have ported the version 1.3.0 to my PowerPC running SMX RTOS and a runtime system which enables me to input and save
commands over telnet into the runtime system. The connection between the programming pc and the runtime system in PowerPC
is done over Ethernet. Everything is well until the PowerPC  sends a big packet (the biggest so far is 500+ bytes)
with checksum error (retransmissions also have checksum error)
and halts the programming interface of the prog.pc since it awaits response from the PowerPC.

At the same time I have a small HTTP server running on the PowerPC and the same case is noticed when the server needs to send
a big packet. Anyways the stack didnt crash due to the error. I sent some stray IP packets and the ICMP module returned me
the normal Destination Unavailable message. Has anyone faced the same problem ?

I enclosed my opt.h and a wireshark trace as an example. I hope someone can give me some tips on the problem as I have been
spending days trying to figure out the problem. I d appreciate any help I can get.

Thanks in advance

M Ikhwan Ismail
ABB STOTZ KONTAKT GmbH
Heidelberg, Germany

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opt.h
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ec500trace.pcap
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