[lwip-users] RE: [lwip] Issues with lwIP on M16C platform

[Josh Marshall]

Leon,

Thanks for your reply.

I do have the DEBUGF output working, over a RS-232 link, and just use
HyperTerminal to view the output. As a clarification, I used the 'echo'
from the minimal arch, and it works fine. (As a sidenote; when I enable
DEBUG, ping takes approx. 700 ms, with it off, it takes < 10 ms)

By seeing if the packet sizes are right, do you mean: See what size
packets are transmitted using Ethereal, and then see if DEBUGF gives the
same answer?

Thanks for your help,

Josh



-----Original Message-----
From: address@hidden [mailto:address@hidden On Behalf Of Leon
Woestenberg
Sent: Tuesday, 22 October 2002 11:11 PM
To: address@hidden
Subject: Re: [lwip] Issues with lwIP on M16C platform


Hello John,

we are using the Infineon C16x architecture, which is a bit similar,
along with 16-bit driven CS8900A.

> I am using IE 6.0 to try and connect to the onboard server. However, 
> after the connection succeeds, the stack crashes, just after receiving

> a packet it thinks is 13k!! The crash comes as an assertion failure 
> when pbuf_free() is called by tcp_recved().
>
My suggestion is this: try to get DEBUGF output working first. Then,
start at the low levels: simply ICMP ping and see if the packet sizes
are right. Try even and uneven sized packets.

Then work your way up to IP and try to follow the debug output; see if
it makes sense.

Having a network analyzer program helped me a lot. (I'm using "Ethereal"
that is available for free, available on most *nixes & Windows.) It
allows you to match packet headers with what lwIP thinks the headers
are.

> Has anyone come across a similar problem? I can't seem to figure it 
> out, with my limited TCP knowledge.
>
My TCP knowledge is limited also in the sense that I have to look up
actual supposed behaviour. I suspect the problem to be in the lower
layers, maybe even down to the ethernet driver.

Re-check the arch files and lwipopts.h files. These have the most
impact. Check for endianness and alignment.

Once I got the lower layers to work, TCP worked OK.

Regards,

Leon.
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