Re: Wrong MAC in redirected packet

[Kristian Evensen <kristian.evensen@gmail.com>]

Jan Engelhardt skrev:
> On Thursday 2009-03-26 11:26, Kristian Evensen wrote:
>   
>> Turned out that it was the checksums. They were calculated correctly,
>> but since I processed packets on input, tcp_hdr and udp_hdr of course
>> returned invalid pointers. My code is now more or less RAWNAT, so if
>> it is of interest to anybody else I will merge them and make it
>> available.
>>     
>
> I have now rebased the RAWNAT branch to Xt-a's master and
> made the rawpost tables workable with all kernel versions.
> It does not have MAC addr punning yet.
>   
Great, but I think I see a small bug (I left my Linux-machine at work so 
I am not able to try it out). If you use RAWDNAT in prerouting, tcp_hdr 
and udp_hdr will return the wrong values since the corresponsing values 
in the SKB are not set yet. At least, that is what I experienced in my 
own module. Please let me know if I am wrong :)

Would a better solution by to use conntrack to determine the direction, 
check the name of the chain (is that possible?) or just simply ip_hdr + 
1? :)

-Kristian