Re: [lwip-users] UDP packet sending problem

[Kieran Mansley]

On Mon, 2009-06-29 at 15:16 +0200, patrick Deflandre wrote:
> So I give you 4 files for 2 tests.
> 
> 1 )  The first set is for a tcp connection : tcp_test.pcap ,
> tcp_test.trace.txt.

Looks fine.

> 2)  The second set is for an udp echo test. udp_echo.pcap ,
> udp_echo.trace.txt

One thing I notice when comparing the two captures is that the second
has a lot of other ARP traffic in it.  I wonder if that could be part of
the problem.  I don't know why this features in the UDP capture and not
the TCP one.  

As the trace file showed that the UDP reply is being sent by the stack
and getting as far as etharp_output() I think this has got to be where
things go wrong.  The gratuitous ARP also points to an ARP problem too.
By adding some tracing to that function you should be able to quickly
see what's going on.

Kieran