Re: LVS-NAT and source routing

[Patrick McHardy <kaber@trash.net>]

Horms wrote:
> On Tue, Aug 29, 2006 at 11:06:37AM +0200, Patrick McHardy wrote:
> 
>>ip_route_me_harder is meant for the opposite case, rerouting locally
>>originating packets as if they were forwarded (if the source is
>>non-local). For your case just calling ip_route_output_key should be
>>faster since it saves the inet_addr_type call. I think nf_ip_reroute
>>doesn't help much since you always seem to change the source address,
>>but you could make the whole thing depend on CONFIG_IP_MULTIPLE_TABLES.
> 
> 
> I took a look into this. It seems that the real key is to avoid
> uneccesary calls to inet_addr_type(). But it seems that the rest
> of ip_route_me_harder() really is needed for ip_vs. If that isn't
> correct, please set me straight.
> 
> But if it is correct, it really does mean a fair ammount of duplicated
> code going into ip_vs_core.c. I wonder if a better option would be
> to allow the addr_type to be passed to ip_route_me_harder(). I have
> a patch below which expresses this idea. It has the nice advantage
> of offering the scope for other callers to supply the addr_type if it
> is known, though I am not sure that this can be the case.


Usually not, but your patch looks fine anyway. We might even be able
to remove the largely duplicated route_reverse() in ipt_REJECT if
we use LL_MAX_HEADER instead of LL_RESERVED_SPACE for the RST packet
(since we would need to route after allocating the packet and
reversing the addresses).