lwIP_Demo_Rowley_ARM7 crash with a ping

pdesii wrote on Friday, March 14, 2008:

lwIP_Demo_Rowley_ARM7 seems to crash if I make a ping with big packet.

The ping used is:
ping -l 4096

I compiled the project with gcc.

Someone can confirm me the problem?
Someone can help me?

Thanks a lot for your time.


rtel wrote on Friday, March 14, 2008:

I imagine this is something to do with the buffer sizes.  Am I right in assuming that pings of size less than 1500 work ok?


pdesii wrote on Monday, March 17, 2008:

Yes, you are right. It works well with ping until 2000 byte. Then, with bigger ping,  application crashes; if some packet was discarded, it have been not a big problem, but crashing, all application is unusable.
I tried to change al lot of lwip options, but the result was always the same.
I am very sorry, … but I have no more ideas!! (:<)


dsvend wrote on Tuesday, March 18, 2008:

i have run into the same problem and I had it fixed when I disabled ip frag and ip reassembly
at lwiopt.h

You could try the lwip forum too, there are some bugs in pbuf.c that they say it would cause this problem, but when I download a newer pbuf.c, version 1.86, the bug persisted.

So the solution was to add these two lines to lwiopts.h

#define IP_FRAG 0

hope it helps.