RE: [lwip-users] Reassembles incoming IP crash my system

[Amir Bukhari]

It was alignment issue, I have used 4 byte alignment and thus case alignment
exception (PPC) to occure. 
In one machine of two machine, which has MPC5200, an alignment exception is
occure and in the other is just crash, before the exception run, I don't
know why.
But as I used 2 byte alignment it work as expected.

-Amir

-----Original Message-----
From: Christiaan Simons [mailto:address@hidden 
Sent: Tuesday, March 21, 2006 9:17 AM
To: address@hidden
Subject: Re: [lwip-users] Reassembles incoming IP crash my system



Amir wrote:

> I am using lwip under mpc5200 and it work fine, until a client send a 
> big
IP
> packet. In this case the lwip crash on
> Ip_frag.c: line 263
> memcpy(q->payload, &ip_reassbuf[i],
>             q->len > ip_reasslen - i ? ip_reasslen - i : q->len);
>
> Then I disable reasemble big IP in lwipopts.h, so that such packets 
> will
be
> droped.
>
> It crash in my case by using "ping" like:
>
> Ping host -s 1524
>
> Is that a bug or I have may forgot something?



Yes, I also found this piece of code a bit suspect / not robust.

I had to fix a bug in my network driver to get this in a workable state.

Make sure your ethernet driver uses correct MTU, then it should work.



Bye,


Christiaan Simons

Hardware Designer
Axon Digital Design

http://www.axon.tv