Re: [lwip-users] problems and solutions (?)

[Uwe Roth]

Hi Kieran,

I'll follow your suggestion to inform you about problems I encountered. I'm
working on a XC161-Board with CS8900a using GNU-C (from Hightec). I tried to
build an easy webserver application using the minimal unix 'echo server'
application as an example how to use the raw api.

It didn't work. Not even the TCP SYN frame from the browser of my PC had
been answered by lwip. The reason for this was that a call to pbuf_header()
from etharp_output() failed because there was not enough space allocated for
the pbuf to hold the link layer header.

I was able to fix this by changing the definition of PBUF_LINK_HLEN (which
was set to 0 !?) in opt.h to the actual size of 14 for the link layer
header. Afterwards everything seemed to work quite well.

Are there any applications or drivers where a definition of

#define PBUF_LINK_HLEN        0

makes any sense?

Uwe