Re: Kernel Routing sequence

From: Al Boldi
Date: Mon Aug 15 2005 - 14:50:20 EST


Soininen Jonne (Nokia-NET/Helsinki) wrote:
> Al, why are you worried that the echo reply goes out from a
> different interface? It might be easier to understand what you want
> if we would understand the problem.

The problem is that the kernel is routing according to a fixed view of
allowed subnets, ie: overlapping subnets are not treated distinctly.

It should be possible for the kernel to detect an IP subnet-collision
on packet pickup, something like:

eth0 is listening on 10.0.0.0/8
eth0 picks up 10.0.1.2 on 10.0.0.0/8
kernel checks the route table
kernel discovers collision with 10.0.1.0/24 on eth1
kernel adds 10.0.1.2/32 route on eth0 to ensure correct routing for
return packets

This behaviour should be the default and be transparent.

This is the idea, although it will eventually overflow the route
table.

--
Al
-
To unsubscribe from this list: send the line "unsubscribe linux-net" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html