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Re: No joy on the network so far


Chuck McManis <ecos@mcmanis.com> writes:

> Well, its curiouser and curiouser ;-)
> 
> Ok, so I've got my new driver written. Started with the rhine driver
> but pretty much replaced everything except the buffer handling code.
> 
> I added some instrumentation to see packets being transmitted as well
> as packets being received. I've got tcpdump of course.
> 
> In order to simplify things I configured redboot to NOT use bootp and
> instead merely assign the address 192.168.110.177 directly.
> 
> It does, and it comes up to the redboot prompt, but if I try to ping
> my server (on the same subnet) it can't see it. Now tcpdump(8) can see
> my target board send out an ARP request for the server, and it sees
> the response. The printf's in the ethernet driver are showing that the
> ethernet chip is seeing those packets as well and fetching them in the
> _recv() function. But they never seem to make up into the networking
> stack where they belong.
> 
> The weird thing is that with teh FXP driver configured this thing
> works entirely as expected so I don't think there are issues with my
> repository being out of date or something.
> 
> What information can I provide that might give someone a clue about
> what is going on here?

Have you tried pinging your target board from your host. I usually
find this is a easier way of testing basic ethernet functionality.

You may need to trace the received packets further up into the redboot
IP stack. One possibility is that there's a fencepost problem and
something like the checksum is failing. Printing out whole packets
using diag_dump_buf() in the driver can often show where data is being
scrambled -- although this does require a bit of familiarity with
ethernet and IP packet formats.

It is almost certain to be a problem in the ethernet driver, but you
need to find out why the packets are being dropped in the IP stack to
find out what is going wrong lower down.

-- 
Nick Garnett                                          eCos Kernel Architect
http://www.ecoscentric.com                     The eCos and RedBoot experts
Besuchen Sie uns vom 14.-16.02.06 auf der Embedded World 2006, Stand 11-222
Visit us at Embedded World 2006, NÃrnberg, Germany, 14-16 Feb, Stand 11-222


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