Re: Question about IP rerouting at POST_ROUTE_HOOK

[Patrick McHardy <kaber@trash.net>]

Glenn.Swonk@tais.com wrote:
> I have written a netfilter module that loads as a kernel loadable module.
> 
> I am hooking into the NF_IP_POST_ROUTING hook.
> 
> I am trying to change the destination (IP address) of the packet at this
> point and am having a problem.
> 
> I am able to change the dest IP address but it is sent out with the
> original IP destination's  MAC address.
> 
> I cannot seem to change the destination MAC address at this point.

You need to make a new route lookup with the changed IP.
The easiest way of doing so is using ip_route_me_harder, it also
does all the work like relocating the packet if the headroom is
too small for the new output device etc.

Regards
Patrick

> 
> Is there a problem with changing the IP address (by manipulation of the
> skbuf data structure) or
> is a better method.
> 
> Any suggestions?
> 
> thanks,
> glenn
> 
> 
> 
> 
> 
> 
> 
> Glenn Swonk
> Toshiba America Information System
> 9740 Irvine Blvd.
> Irvine, CA 92618
> 
> 949-587-6530
> gswonk at tais.com
> 
> Not Done = Less than 100%
> Testing is never finished, only abandoned...
> 
>