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

[Leon Woestenberg]

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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