[lwip-users] ip forward and pbuf corruption

[Tyrel Newton]

I have a system with two netifs and I'm trying to forward packets 
between the two interfaces. One netif is my Ethernet interface while the 
other is a custom wireless interface. The problem is that the forwarded 
pbuf is getting corrupted somehow before I can send it back out. At 
first I thought the forwarded pbuf was getting free'd prematurely, but 
an additional pbuf_ref does not fix the problem. I know the pbuf enters 
my second netif correctly, but before I can get it sent out, its either 
being free'd or modified somehow again. At the moment its working, but 
its because I'm copying the forwarded pbuf before sending it back out.

I have gone over the code numerous times and traced the pbuf from the rx 
of my ethernet interface, through the etharp code, through ip forward, 
and into my second netif driver and I can't figure out where the problem 
is. I'm currently running the latest code in the git repo (as of yesterday).

Does anybody have any clues as to where to look for the problem? My 
guess is that its somewhere in the etharp code, but I can't find it. 
Copying the entire pbuf is not exactly a good solution, though it 
definitely works.

Thanks,
Tyrel